"use strict";

var htmlNamespace = "http://www.w3.org/1999/xhtml";

var cssStylingFlag = false;

var defaultSingleLineContainerName = "p";

// This is bad :(
var globalRange = null;

// Commands are stored in a dictionary where we call their actions and such
var commands = {};

///////////////////////////////////////////////////////////////////////////////
////////////////////////////// Utility functions //////////////////////////////
///////////////////////////////////////////////////////////////////////////////
//@{

function nextNode(node) {
  if (node.hasChildNodes()) {
    return node.firstChild;
  }
  return nextNodeDescendants(node);
}

function previousNode(node) {
  if (node.previousSibling) {
    node = node.previousSibling;
    while (node.hasChildNodes()) {
      node = node.lastChild;
    }
    return node;
  }
  if (node.parentNode
  && node.parentNode.nodeType == Node.ELEMENT_NODE) {
    return node.parentNode;
  }
  return null;
}

function nextNodeDescendants(node) {
  while (node && !node.nextSibling) {
    node = node.parentNode;
  }
  if (!node) {
    return null;
  }
  return node.nextSibling;
}

/**
 * Returns true if ancestor is an ancestor of descendant, false otherwise.
 */
function isAncestor(ancestor, descendant) {
  return ancestor
    && descendant
    && Boolean(ancestor.compareDocumentPosition(descendant) & Node.DOCUMENT_POSITION_CONTAINED_BY);
}

/**
 * Returns true if ancestor is an ancestor of or equal to descendant, false
 * otherwise.
 */
function isAncestorContainer(ancestor, descendant) {
  return (ancestor || descendant)
    && (ancestor == descendant || isAncestor(ancestor, descendant));
}

/**
 * Returns true if descendant is a descendant of ancestor, false otherwise.
 */
function isDescendant(descendant, ancestor) {
  return ancestor
    && descendant
    && Boolean(ancestor.compareDocumentPosition(descendant) & Node.DOCUMENT_POSITION_CONTAINED_BY);
}

/**
 * Returns true if node1 is before node2 in tree order, false otherwise.
 */
function isBefore(node1, node2) {
  return Boolean(node1.compareDocumentPosition(node2) & Node.DOCUMENT_POSITION_FOLLOWING);
}

/**
 * Returns true if node1 is after node2 in tree order, false otherwise.
 */
function isAfter(node1, node2) {
  return Boolean(node1.compareDocumentPosition(node2) & Node.DOCUMENT_POSITION_PRECEDING);
}

function getAncestors(node) {
  var ancestors = [];
  while (node.parentNode) {
    ancestors.unshift(node.parentNode);
    node = node.parentNode;
  }
  return ancestors;
}

function getInclusiveAncestors(node) {
  return getAncestors(node).concat(node);
}

function getDescendants(node) {
  var descendants = [];
  var stop = nextNodeDescendants(node);
  while ((node = nextNode(node))
  && node != stop) {
    descendants.push(node);
  }
  return descendants;
}

function getInclusiveDescendants(node) {
  return [node].concat(getDescendants(node));
}

function convertProperty(property) {
  // Special-case for now
  var map = {
    "fontFamily": "font-family",
    "fontSize": "font-size",
    "fontStyle": "font-style",
    "fontWeight": "font-weight",
    "textDecoration": "text-decoration",
  };
  if (typeof map[property] != "undefined") {
    return map[property];
  }

  return property;
}

// Return the <font size=X> value for the given CSS size, or undefined if there
// is none.
function cssSizeToLegacy(cssVal) {
  return {
    "x-small": 1,
    "small": 2,
    "medium": 3,
    "large": 4,
    "x-large": 5,
    "xx-large": 6,
    "xxx-large": 7
  }[cssVal];
}

// Return the CSS size given a legacy size.
function legacySizeToCss(legacyVal) {
  return {
    1: "x-small",
    2: "small",
    3: "medium",
    4: "large",
    5: "x-large",
    6: "xx-large",
    7: "xxx-large",
  }[legacyVal];
}

// Opera 11 puts HTML elements in the null namespace, it seems.
function isHtmlNamespace(ns) {
  return ns === null
    || ns === htmlNamespace;
}

// "the directionality" from HTML.  I don't bother caring about non-HTML
// elements.
//
// "The directionality of an element is either 'ltr' or 'rtl', and is
// determined as per the first appropriate set of steps from the following
// list:"
function getDirectionality(element) {
  // "If the element's dir attribute is in the ltr state
  //     The directionality of the element is 'ltr'."
  if (element.dir == "ltr") {
    return "ltr";
  }

  // "If the element's dir attribute is in the rtl state
  //     The directionality of the element is 'rtl'."
  if (element.dir == "rtl") {
    return "rtl";
  }

  // "If the element's dir attribute is in the auto state
  // "If the element is a bdi element and the dir attribute is not in a
  // defined state (i.e. it is not present or has an invalid value)
  //     [lots of complicated stuff]
  //
  // Skip this, since no browser implements it anyway.

  // "If the element is a root element and the dir attribute is not in a
  // defined state (i.e. it is not present or has an invalid value)
  //     The directionality of the element is 'ltr'."
  if (!isHtmlElement(element.parentNode)) {
    return "ltr";
  }

  // "If the element has a parent element and the dir attribute is not in a
  // defined state (i.e. it is not present or has an invalid value)
  //     The directionality of the element is the same as the element's
  //     parent element's directionality."
  return getDirectionality(element.parentNode);
}

//@}

///////////////////////////////////////////////////////////////////////////////
///////////////////////////// DOM Range functions /////////////////////////////
///////////////////////////////////////////////////////////////////////////////
//@{

function getNodeIndex(node) {
  var ret = 0;
  while (node.previousSibling) {
    ret++;
    node = node.previousSibling;
  }
  return ret;
}

// "The length of a Node node is the following, depending on node:
//
// ProcessingInstruction
// DocumentType
//   Always 0.
// Text
// Comment
//   node's length.
// Any other node
//   node's childNodes's length."
function getNodeLength(node) {
  switch (node.nodeType) {
    case Node.PROCESSING_INSTRUCTION_NODE:
    case Node.DOCUMENT_TYPE_NODE:
      return 0;

    case Node.TEXT_NODE:
    case Node.COMMENT_NODE:
      return node.length;

    default:
      return node.childNodes.length;
  }
}

/**
 * The position of two boundary points relative to one another, as defined by
 * DOM Range.
 */
function getPosition(nodeA, offsetA, nodeB, offsetB) {
  // "If node A is the same as node B, return equal if offset A equals offset
  // B, before if offset A is less than offset B, and after if offset A is
  // greater than offset B."
  if (nodeA == nodeB) {
    if (offsetA == offsetB) {
      return "equal";
    }
    if (offsetA < offsetB) {
      return "before";
    }
    if (offsetA > offsetB) {
      return "after";
    }
  }

  // "If node A is after node B in tree order, compute the position of (node
  // B, offset B) relative to (node A, offset A). If it is before, return
  // after. If it is after, return before."
  if (nodeB.compareDocumentPosition(nodeA) & Node.DOCUMENT_POSITION_FOLLOWING) {
    var pos = getPosition(nodeB, offsetB, nodeA, offsetA);
    if (pos == "before") {
      return "after";
    }
    if (pos == "after") {
      return "before";
    }
  }

  // "If node A is an ancestor of node B:"
  if (nodeB.compareDocumentPosition(nodeA) & Node.DOCUMENT_POSITION_CONTAINS) {
    // "Let child equal node B."
    var child = nodeB;

    // "While child is not a child of node A, set child to its parent."
    while (child.parentNode != nodeA) {
      child = child.parentNode;
    }

    // "If the index of child is less than offset A, return after."
    if (getNodeIndex(child) < offsetA) {
      return "after";
    }
  }

  // "Return before."
  return "before";
}

/**
 * Returns the furthest ancestor of a Node as defined by DOM Range.
 */
function getFurthestAncestor(node) {
  var root = node;
  while (root.parentNode != null) {
    root = root.parentNode;
  }
  return root;
}

/**
 * "contained" as defined by DOM Range: "A Node node is contained in a range
 * range if node's furthest ancestor is the same as range's root, and (node, 0)
 * is after range's start, and (node, length of node) is before range's end."
 */
function isContained(node, range) {
  var pos1 = getPosition(node, 0, range.startContainer, range.startOffset);
  var pos2 = getPosition(node, getNodeLength(node), range.endContainer, range.endOffset);

  return getFurthestAncestor(node) == getFurthestAncestor(range.startContainer)
    && pos1 == "after"
    && pos2 == "before";
}

/**
 * Return all nodes contained in range that the provided function returns true
 * for, omitting any with an ancestor already being returned.
 */
function getContainedNodes(range, condition) {
  if (typeof condition == "undefined") {
    condition = function() { return true };
  }
  var node = range.startContainer;
  if (node.hasChildNodes()
  && range.startOffset < node.childNodes.length) {
    // A child is contained
    node = node.childNodes[range.startOffset];
  } else if (range.startOffset == getNodeLength(node)) {
    // No descendant can be contained
    node = nextNodeDescendants(node);
  } else {
    // No children; this node at least can't be contained
    node = nextNode(node);
  }

  var stop = range.endContainer;
  if (stop.hasChildNodes()
  && range.endOffset < stop.childNodes.length) {
    // The node after the last contained node is a child
    stop = stop.childNodes[range.endOffset];
  } else {
    // This node and/or some of its children might be contained
    stop = nextNodeDescendants(stop);
  }

  var nodeList = [];
  while (isBefore(node, stop)) {
    if (isContained(node, range)
    && condition(node)) {
      nodeList.push(node);
      node = nextNodeDescendants(node);
      continue;
    }
    node = nextNode(node);
  }
  return nodeList;
}

/**
 * As above, but includes nodes with an ancestor that's already been returned.
 */
function getAllContainedNodes(range, condition) {
  if (typeof condition == "undefined") {
    condition = function() { return true };
  }
  var node = range.startContainer;
  if (node.hasChildNodes()
  && range.startOffset < node.childNodes.length) {
    // A child is contained
    node = node.childNodes[range.startOffset];
  } else if (range.startOffset == getNodeLength(node)) {
    // No descendant can be contained
    node = nextNodeDescendants(node);
  } else {
    // No children; this node at least can't be contained
    node = nextNode(node);
  }

  var stop = range.endContainer;
  if (stop.hasChildNodes()
  && range.endOffset < stop.childNodes.length) {
    // The node after the last contained node is a child
    stop = stop.childNodes[range.endOffset];
  } else {
    // This node and/or some of its children might be contained
    stop = nextNodeDescendants(stop);
  }

  var nodeList = [];
  while (isBefore(node, stop)) {
    if (isContained(node, range)
    && condition(node)) {
      nodeList.push(node);
    }
    node = nextNode(node);
  }
  return nodeList;
}

// Returns either null, or something of the form rgb(x, y, z), or something of
// the form rgb(x, y, z, w) with w != 0.
function normalizeColor(color) {
  if (color.toLowerCase() == "currentcolor") {
    return null;
  }

  if (normalizeColor.resultCache === undefined) {
    normalizeColor.resultCache = {};
  }

  if (normalizeColor.resultCache[color] !== undefined) {
    return normalizeColor.resultCache[color];
  }

  var originalColor = color;

  var outerSpan = document.createElement("span");
  document.body.appendChild(outerSpan);
  outerSpan.style.color = "black";

  var innerSpan = document.createElement("span");
  outerSpan.appendChild(innerSpan);
  innerSpan.style.color = color;
  color = getComputedStyle(innerSpan).color;

  if (color == "rgb(0, 0, 0)") {
    // Maybe it's really black, maybe it's invalid.
    outerSpan.color = "white";
    color = getComputedStyle(innerSpan).color;
    if (color != "rgb(0, 0, 0)") {
      return normalizeColor.resultCache[originalColor] = null;
    }
  }

  document.body.removeChild(outerSpan);

  // I rely on the fact that browsers generally provide consistent syntax for
  // getComputedStyle(), although it's not standardized.  There are only
  // three exceptions I found:
  if (/^rgba\([0-9]+, [0-9]+, [0-9]+, 1\)$/.test(color)) {
    // IE10PP2 seems to do this sometimes.
    return normalizeColor.resultCache[originalColor] =
      color.replace("rgba", "rgb").replace(", 1)", ")");
  }
  if (color == "transparent") {
    // IE10PP2, Firefox 7.0a2, and Opera 11.50 all return "transparent" if
    // the specified value is "transparent".
    return normalizeColor.resultCache[originalColor] =
      "rgba(0, 0, 0, 0)";
  }
  // Chrome 15 dev adds way too many significant figures.  This isn't a full
  // fix, it just fixes one case that comes up in tests.
  color = color.replace(/, 0.496094\)$/, ", 0.5)");
  return normalizeColor.resultCache[originalColor] = color;
}

// Returns either null, or something of the form #xxxxxx.
function parseSimpleColor(color) {
  color = normalizeColor(color);
  var matches = /^rgb\(([0-9]+), ([0-9]+), ([0-9]+)\)$/.exec(color);
  if (matches) {
    return "#"
      + parseInt(matches[1]).toString(16).replace(/^.$/, "0$&")
      + parseInt(matches[2]).toString(16).replace(/^.$/, "0$&")
      + parseInt(matches[3]).toString(16).replace(/^.$/, "0$&");
  }
  return null;
}

//@}

//////////////////////////////////////////////////////////////////////////////
/////////////////////////// Edit command functions ///////////////////////////
//////////////////////////////////////////////////////////////////////////////

/////////////////////////////////////////////////
///// Methods of the HTMLDocument interface /////
/////////////////////////////////////////////////
//@{

var executionStackDepth = 0;

// Helper function for common behavior.
function editCommandMethod(command, range, callback) {
  // Set up our global range magic, but only if we're the outermost function
  if (executionStackDepth == 0 && typeof range != "undefined") {
    globalRange = range;
  } else if (executionStackDepth == 0) {
    globalRange = null;
    globalRange = getActiveRange();
  }

  executionStackDepth++;
  try {
    var ret = callback();
  } catch(e) {
    executionStackDepth--;
    throw e;
  }
  executionStackDepth--;
  return ret;
}

function myExecCommand(command, showUi, value, range) {
  // "All of these methods must treat their command argument ASCII
  // case-insensitively."
  command = command.toLowerCase();

  // "If only one argument was provided, let show UI be false."
  //
  // If range was passed, I can't actually detect how many args were passed
  // . . .
  if (arguments.length == 1
  || (arguments.length >=4 && typeof showUi == "undefined")) {
    showUi = false;
  }

  // "If only one or two arguments were provided, let value be the empty
  // string."
  if (arguments.length <= 2
  || (arguments.length >=4 && typeof value == "undefined")) {
    value = "";
  }

  return editCommandMethod(command, range, (function(command, showUi, value) { return function() {
    // "If command is not supported or not enabled, return false."
    if (!(command in commands) || !myQueryCommandEnabled(command)) {
      return false;
    }

    // "Take the action for command, passing value to the instructions as an
    // argument."
    var ret = commands[command].action(value);

    // Check for bugs
    if (ret !== true && ret !== false) {
      throw "execCommand() didn't return true or false: " + ret;
    }

    // "If the previous step returned false, return false."
    if (ret === false) {
      return false;
    }

    // "Return true."
    return true;
  }})(command, showUi, value));
}

function myQueryCommandEnabled(command, range) {
  // "All of these methods must treat their command argument ASCII
  // case-insensitively."
  command = command.toLowerCase();

  return editCommandMethod(command, range, (function(command) { return function() {
    // "Return true if command is both supported and enabled, false
    // otherwise."
    if (!(command in commands)) {
      return false;
    }

    // "Among commands defined in this specification, those listed in
    // Miscellaneous commands are always enabled, except for the cut
    // command and the paste command. The other commands defined here are
    // enabled if the active range is not null, its start node is either
    // editable or an editing host, its end node is either editable or an
    // editing host, and there is some editing host that is an inclusive
    // ancestor of both its start node and its end node."
    return ["copy", "defaultparagraphseparator", "selectall", "stylewithcss",
    "usecss"].indexOf(command) != -1
      || (
        getActiveRange() !== null
        && (isEditable(getActiveRange().startContainer) || isEditingHost(getActiveRange().startContainer))
        && (isEditable(getActiveRange().endContainer) || isEditingHost(getActiveRange().endContainer))
        && (getInclusiveAncestors(getActiveRange().commonAncestorContainer).some(isEditingHost))
      );
  }})(command));
}

function myQueryCommandIndeterm(command, range) {
  // "All of these methods must treat their command argument ASCII
  // case-insensitively."
  command = command.toLowerCase();

  return editCommandMethod(command, range, (function(command) { return function() {
    // "If command is not supported or has no indeterminacy, return false."
    if (!(command in commands) || !("indeterm" in commands[command])) {
      return false;
    }

    // "Return true if command is indeterminate, otherwise false."
    return commands[command].indeterm();
  }})(command));
}

function myQueryCommandState(command, range) {
  // "All of these methods must treat their command argument ASCII
  // case-insensitively."
  command = command.toLowerCase();

  return editCommandMethod(command, range, (function(command) { return function() {
    // "If command is not supported or has no state, return false."
    if (!(command in commands) || !("state" in commands[command])) {
      return false;
    }

    // "If the state override for command is set, return it."
    if (typeof getStateOverride(command) != "undefined") {
      return getStateOverride(command);
    }

    // "Return true if command's state is true, otherwise false."
    return commands[command].state();
  }})(command));
}

// "When the queryCommandSupported(command) method on the HTMLDocument
// interface is invoked, the user agent must return true if command is
// supported, and false otherwise."
function myQueryCommandSupported(command) {
  // "All of these methods must treat their command argument ASCII
  // case-insensitively."
  command = command.toLowerCase();

  return command in commands;
}

function myQueryCommandValue(command, range) {
  // "All of these methods must treat their command argument ASCII
  // case-insensitively."
  command = command.toLowerCase();

  return editCommandMethod(command, range, function() {
    // "If command is not supported or has no value, return the empty string."
    if (!(command in commands) || !("value" in commands[command])) {
      return "";
    }

    // "If command is "fontSize" and its value override is set, convert the
    // value override to an integer number of pixels and return the legacy
    // font size for the result."
    if (command == "fontsize"
    && getValueOverride("fontsize") !== undefined) {
      return getLegacyFontSize(getValueOverride("fontsize"));
    }

    // "If the value override for command is set, return it."
    if (typeof getValueOverride(command) != "undefined") {
      return getValueOverride(command);
    }

    // "Return command's value."
    return commands[command].value();
  });
}
//@}

//////////////////////////////
///// Common definitions /////
//////////////////////////////
//@{

// "An HTML element is an Element whose namespace is the HTML namespace."
//
// I allow an extra argument to more easily check whether something is a
// particular HTML element, like isHtmlElement(node, "OL").  It accepts arrays
// too, like isHtmlElement(node, ["OL", "UL"]) to check if it's an ol or ul.
function isHtmlElement(node, tags) {
  if (typeof tags == "string") {
    tags = [tags];
  }
  if (typeof tags == "object") {
    tags = tags.map(function(tag) { return tag.toUpperCase() });
  }
  return node
    && node.nodeType == Node.ELEMENT_NODE
    && isHtmlNamespace(node.namespaceURI)
    && (typeof tags == "undefined" || tags.indexOf(node.tagName) != -1);
}

// "A prohibited paragraph child name is "address", "article", "aside",
// "blockquote", "caption", "center", "col", "colgroup", "dd", "details",
// "dir", "div", "dl", "dt", "fieldset", "figcaption", "figure", "footer",
// "form", "h1", "h2", "h3", "h4", "h5", "h6", "header", "hgroup", "hr", "li",
// "listing", "menu", "nav", "ol", "p", "plaintext", "pre", "section",
// "summary", "table", "tbody", "td", "tfoot", "th", "thead", "tr", "ul", or
// "xmp"."
var prohibitedParagraphChildNames = ["address", "article", "aside",
  "blockquote", "caption", "center", "col", "colgroup", "dd", "details",
  "dir", "div", "dl", "dt", "fieldset", "figcaption", "figure", "footer",
  "form", "h1", "h2", "h3", "h4", "h5", "h6", "header", "hgroup", "hr", "li",
  "listing", "menu", "nav", "ol", "p", "plaintext", "pre", "section",
  "summary", "table", "tbody", "td", "tfoot", "th", "thead", "tr", "ul",
  "xmp"];

// "A prohibited paragraph child is an HTML element whose local name is a
// prohibited paragraph child name."
function isProhibitedParagraphChild(node) {
  return isHtmlElement(node, prohibitedParagraphChildNames);
}

// "A block node is either an Element whose "display" property does not have
// resolved value "inline" or "inline-block" or "inline-table" or "none", or a
// Document, or a DocumentFragment."
function isBlockNode(node) {
  return node
    && ((node.nodeType == Node.ELEMENT_NODE && ["inline", "inline-block", "inline-table", "none"].indexOf(getComputedStyle(node).display) == -1)
    || node.nodeType == Node.DOCUMENT_NODE
    || node.nodeType == Node.DOCUMENT_FRAGMENT_NODE);
}

// "An inline node is a node that is not a block node."
function isInlineNode(node) {
  return node && !isBlockNode(node);
}

// "An editing host is a node that is either an HTML element with a
// contenteditable attribute set to the true state, or the HTML element child
// of a Document whose designMode is enabled."
function isEditingHost(node) {
  return node
    && isHtmlElement(node)
    && (node.contentEditable == "true"
    || (node.parentNode
    && node.parentNode.nodeType == Node.DOCUMENT_NODE
    && node.parentNode.designMode == "on"));
}

// "Something is editable if it is a node; it is not an editing host; it does
// not have a contenteditable attribute set to the false state; its parent is
// an editing host or editable; and either it is an HTML element, or it is an
// svg or math element, or it is not an Element and its parent is an HTML
// element."
function isEditable(node) {
  return node
    && !isEditingHost(node)
    && (node.nodeType != Node.ELEMENT_NODE || node.contentEditable != "false")
    && (isEditingHost(node.parentNode) || isEditable(node.parentNode))
    && (isHtmlElement(node)
    || (node.nodeType == Node.ELEMENT_NODE && node.namespaceURI == "http://www.w3.org/2000/svg" && node.localName == "svg")
    || (node.nodeType == Node.ELEMENT_NODE && node.namespaceURI == "http://www.w3.org/1998/Math/MathML" && node.localName == "math")
    || (node.nodeType != Node.ELEMENT_NODE && isHtmlElement(node.parentNode)));
}

// Helper function, not defined in the spec
function hasEditableDescendants(node) {
  for (var i = 0; i < node.childNodes.length; i++) {
    if (isEditable(node.childNodes[i])
    || hasEditableDescendants(node.childNodes[i])) {
      return true;
    }
  }
  return false;
}

// "The editing host of node is null if node is neither editable nor an editing
// host; node itself, if node is an editing host; or the nearest ancestor of
// node that is an editing host, if node is editable."
function getEditingHostOf(node) {
  if (isEditingHost(node)) {
    return node;
  } else if (isEditable(node)) {
    var ancestor = node.parentNode;
    while (!isEditingHost(ancestor)) {
      ancestor = ancestor.parentNode;
    }
    return ancestor;
  } else {
    return null;
  }
}

// "Two nodes are in the same editing host if the editing host of the first is
// non-null and the same as the editing host of the second."
function inSameEditingHost(node1, node2) {
  return getEditingHostOf(node1)
    && getEditingHostOf(node1) == getEditingHostOf(node2);
}

// "A collapsed line break is a br that begins a line box which has nothing
// else in it, and therefore has zero height."
function isCollapsedLineBreak(br) {
  if (!isHtmlElement(br, "br")) {
    return false;
  }

  // Add a zwsp after it and see if that changes the height of the nearest
  // non-inline parent.  Note: this is not actually reliable, because the
  // parent might have a fixed height or something.
  var ref = br.parentNode;
  while (getComputedStyle(ref).display == "inline") {
    ref = ref.parentNode;
  }
  var refStyle = ref.hasAttribute("style") ? ref.getAttribute("style") : null;
  ref.style.height = "auto";
  ref.style.maxHeight = "none";
  ref.style.minHeight = "0";
  var space = document.createTextNode("\u200b");
  var origHeight = ref.offsetHeight;
  if (origHeight == 0) {
    throw "isCollapsedLineBreak: original height is zero, bug?";
  }
  br.parentNode.insertBefore(space, br.nextSibling);
  var finalHeight = ref.offsetHeight;
  space.parentNode.removeChild(space);
  if (refStyle === null) {
    // Without the setAttribute() line, removeAttribute() doesn't work in
    // Chrome 14 dev.  I have no idea why.
    ref.setAttribute("style", "");
    ref.removeAttribute("style");
  } else {
    ref.setAttribute("style", refStyle);
  }

  // Allow some leeway in case the zwsp didn't create a whole new line, but
  // only made an existing line slightly higher.  Firefox 6.0a2 shows this
  // behavior when the first line is bold.
  return origHeight < finalHeight - 5;
}

// "An extraneous line break is a br that has no visual effect, in that
// removing it from the DOM would not change layout, except that a br that is
// the sole child of an li is not extraneous."
//
// FIXME: This doesn't work in IE, since IE ignores display: none in
// contenteditable.
function isExtraneousLineBreak(br) {
  if (!isHtmlElement(br, "br")) {
    return false;
  }

  if (isHtmlElement(br.parentNode, "li")
  && br.parentNode.childNodes.length == 1) {
    return false;
  }

  // Make the line break disappear and see if that changes the block's
  // height.  Yes, this is an absurd hack.  We have to reset height etc. on
  // the reference node because otherwise its height won't change if it's not
  // auto.
  var ref = br.parentNode;
  while (getComputedStyle(ref).display == "inline") {
    ref = ref.parentNode;
  }
  var refStyle = ref.hasAttribute("style") ? ref.getAttribute("style") : null;
  ref.style.height = "auto";
  ref.style.maxHeight = "none";
  ref.style.minHeight = "0";
  var brStyle = br.hasAttribute("style") ? br.getAttribute("style") : null;
  var origHeight = ref.offsetHeight;
  if (origHeight == 0) {
    throw "isExtraneousLineBreak: original height is zero, bug?";
  }
  br.setAttribute("style", "display:none");
  var finalHeight = ref.offsetHeight;
  if (refStyle === null) {
    // Without the setAttribute() line, removeAttribute() doesn't work in
    // Chrome 14 dev.  I have no idea why.
    ref.setAttribute("style", "");
    ref.removeAttribute("style");
  } else {
    ref.setAttribute("style", refStyle);
  }
  if (brStyle === null) {
    br.removeAttribute("style");
  } else {
    br.setAttribute("style", brStyle);
  }

  return origHeight == finalHeight;
}

// "A whitespace node is either a Text node whose data is the empty string; or
// a Text node whose data consists only of one or more tabs (0x0009), line
// feeds (0x000A), carriage returns (0x000D), and/or spaces (0x0020), and whose
// parent is an Element whose resolved value for "white-space" is "normal" or
// "nowrap"; or a Text node whose data consists only of one or more tabs
// (0x0009), carriage returns (0x000D), and/or spaces (0x0020), and whose
// parent is an Element whose resolved value for "white-space" is "pre-line"."
function isWhitespaceNode(node) {
  return node
    && node.nodeType == Node.TEXT_NODE
    && (node.data == ""
    || (
      /^[\t\n\r ]+$/.test(node.data)
      && node.parentNode
      && node.parentNode.nodeType == Node.ELEMENT_NODE
      && ["normal", "nowrap"].indexOf(getComputedStyle(node.parentNode).whiteSpace) != -1
    ) || (
      /^[\t\r ]+$/.test(node.data)
      && node.parentNode
      && node.parentNode.nodeType == Node.ELEMENT_NODE
      && getComputedStyle(node.parentNode).whiteSpace == "pre-line"
    ));
}

// "node is a collapsed whitespace node if the following algorithm returns
// true:"
function isCollapsedWhitespaceNode(node) {
  // "If node is not a whitespace node, return false."
  if (!isWhitespaceNode(node)) {
    return false;
  }

  // "If node's data is the empty string, return true."
  if (node.data == "") {
    return true;
  }

  // "Let ancestor be node's parent."
  var ancestor = node.parentNode;

  // "If ancestor is null, return true."
  if (!ancestor) {
    return true;
  }

  // "If the "display" property of some ancestor of node has resolved value
  // "none", return true."
  if (getAncestors(node).some(function(ancestor) {
    return ancestor.nodeType == Node.ELEMENT_NODE
      && getComputedStyle(ancestor).display == "none";
  })) {
    return true;
  }

  // "While ancestor is not a block node and its parent is not null, set
  // ancestor to its parent."
  while (!isBlockNode(ancestor)
  && ancestor.parentNode) {
    ancestor = ancestor.parentNode;
  }

  // "Let reference be node."
  var reference = node;

  // "While reference is a descendant of ancestor:"
  while (reference != ancestor) {
    // "Let reference be the node before it in tree order."
    reference = previousNode(reference);

    // "If reference is a block node or a br, return true."
    if (isBlockNode(reference)
    || isHtmlElement(reference, "br")) {
      return true;
    }

    // "If reference is a Text node that is not a whitespace node, or is an
    // img, break from this loop."
    if ((reference.nodeType == Node.TEXT_NODE && !isWhitespaceNode(reference))
    || isHtmlElement(reference, "img")) {
      break;
    }
  }

  // "Let reference be node."
  reference = node;

  // "While reference is a descendant of ancestor:"
  var stop = nextNodeDescendants(ancestor);
  while (reference != stop) {
    // "Let reference be the node after it in tree order, or null if there
    // is no such node."
    reference = nextNode(reference);

    // "If reference is a block node or a br, return true."
    if (isBlockNode(reference)
    || isHtmlElement(reference, "br")) {
      return true;
    }

    // "If reference is a Text node that is not a whitespace node, or is an
    // img, break from this loop."
    if ((reference && reference.nodeType == Node.TEXT_NODE && !isWhitespaceNode(reference))
    || isHtmlElement(reference, "img")) {
      break;
    }
  }

  // "Return false."
  return false;
}

// "Something is visible if it is a node that either is a block node, or a Text
// node that is not a collapsed whitespace node, or an img, or a br that is not
// an extraneous line break, or any node with a visible descendant; excluding
// any node with an ancestor container Element whose "display" property has
// resolved value "none"."
function isVisible(node) {
  if (!node) {
    return false;
  }

  if (getAncestors(node).concat(node)
  .filter(function(node) { return node.nodeType == Node.ELEMENT_NODE })
  .some(function(node) { return getComputedStyle(node).display == "none" })) {
    return false;
  }

  if (isBlockNode(node)
  || (node.nodeType == Node.TEXT_NODE && !isCollapsedWhitespaceNode(node))
  || isHtmlElement(node, "img")
  || (isHtmlElement(node, "br") && !isExtraneousLineBreak(node))) {
    return true;
  }

  for (var i = 0; i < node.childNodes.length; i++) {
    if (isVisible(node.childNodes[i])) {
      return true;
    }
  }

  return false;
}

// "Something is invisible if it is a node that is not visible."
function isInvisible(node) {
  return node && !isVisible(node);
}

// "A collapsed block prop is either a collapsed line break that is not an
// extraneous line break, or an Element that is an inline node and whose
// children are all either invisible or collapsed block props and that has at
// least one child that is a collapsed block prop."
function isCollapsedBlockProp(node) {
  if (isCollapsedLineBreak(node)
  && !isExtraneousLineBreak(node)) {
    return true;
  }

  if (!isInlineNode(node)
  || node.nodeType != Node.ELEMENT_NODE) {
    return false;
  }

  var hasCollapsedBlockPropChild = false;
  for (var i = 0; i < node.childNodes.length; i++) {
    if (!isInvisible(node.childNodes[i])
    && !isCollapsedBlockProp(node.childNodes[i])) {
      return false;
    }
    if (isCollapsedBlockProp(node.childNodes[i])) {
      hasCollapsedBlockPropChild = true;
    }
  }

  return hasCollapsedBlockPropChild;
}

// "The active range is the range of the selection given by calling
// getSelection() on the context object. (Thus the active range may be null.)"
//
// We cheat and return globalRange if that's defined.  We also ensure that the
// active range meets the requirements that selection boundary points are
// supposed to meet, i.e., that the nodes are both Text or Element nodes that
// descend from a Document.
function getActiveRange() {
  var ret;
  if (globalRange) {
    ret = globalRange;
  } else if (getSelection().rangeCount) {
    ret = getSelection().getRangeAt(0);
  } else {
    return null;
  }
  if ([Node.TEXT_NODE, Node.ELEMENT_NODE].indexOf(ret.startContainer.nodeType) == -1
  || [Node.TEXT_NODE, Node.ELEMENT_NODE].indexOf(ret.endContainer.nodeType) == -1
  || !ret.startContainer.ownerDocument
  || !ret.endContainer.ownerDocument
  || !isDescendant(ret.startContainer, ret.startContainer.ownerDocument)
  || !isDescendant(ret.endContainer, ret.endContainer.ownerDocument)) {
    throw "Invalid active range; test bug?";
  }
  return ret;
}

// "For some commands, each HTMLDocument must have a boolean state override
// and/or a string value override. These do not change the command's state or
// value, but change the way some algorithms behave, as specified in those
// algorithms' definitions. Initially, both must be unset for every command.
// Whenever the number of ranges in the Selection changes to something
// different, and whenever a boundary point of the range at a given index in
// the Selection changes to something different, the state override and value
// override must be unset for every command."
//
// We implement this crudely by using setters and getters.  To verify that the
// selection hasn't changed, we copy the active range and just check the
// endpoints match.  This isn't really correct, but it's good enough for us.
// Unset state/value overrides are undefined.  We put everything in a function
// so no one can access anything except via the provided functions, since
// otherwise callers might mistakenly use outdated overrides (if the selection
// has changed).
var getStateOverride, setStateOverride, unsetStateOverride,
  getValueOverride, setValueOverride, unsetValueOverride;
(function() {
  var stateOverrides = {};
  var valueOverrides = {};
  var storedRange = null;

  function resetOverrides() {
    if (!storedRange
    || storedRange.startContainer != getActiveRange().startContainer
    || storedRange.endContainer != getActiveRange().endContainer
    || storedRange.startOffset != getActiveRange().startOffset
    || storedRange.endOffset != getActiveRange().endOffset) {
      stateOverrides = {};
      valueOverrides = {};
      storedRange = getActiveRange().cloneRange();
    }
  }

  getStateOverride = function(command) {
    resetOverrides();
    return stateOverrides[command];
  };

  setStateOverride = function(command, newState) {
    resetOverrides();
    stateOverrides[command] = newState;
  };

  unsetStateOverride = function(command) {
    resetOverrides();
    delete stateOverrides[command];
  }

  getValueOverride = function(command) {
    resetOverrides();
    return valueOverrides[command];
  }

  // "The value override for the backColor command must be the same as the
  // value override for the hiliteColor command, such that setting one sets
  // the other to the same thing and unsetting one unsets the other."
  setValueOverride = function(command, newValue) {
    resetOverrides();
    valueOverrides[command] = newValue;
    if (command == "backcolor") {
      valueOverrides.hilitecolor = newValue;
    } else if (command == "hilitecolor") {
      valueOverrides.backcolor = newValue;
    }
  }

  unsetValueOverride = function(command) {
    resetOverrides();
    delete valueOverrides[command];
    if (command == "backcolor") {
      delete valueOverrides.hilitecolor;
    } else if (command == "hilitecolor") {
      delete valueOverrides.backcolor;
    }
  }
})();

//@}

/////////////////////////////
///// Common algorithms /////
/////////////////////////////

///// Assorted common algorithms /////
//@{

// Magic array of extra ranges whose endpoints we want to preserve.
var extraRanges = [];

function movePreservingRanges(node, newParent, newIndex) {
  // For convenience, I allow newIndex to be -1 to mean "insert at the end".
  if (newIndex == -1) {
    newIndex = newParent.childNodes.length;
  }

  // "When the user agent is to move a Node to a new location, preserving
  // ranges, it must remove the Node from its original parent (if any), then
  // insert it in the new location. In doing so, however, it must ignore the
  // regular range mutation rules, and instead follow these rules:"

  // "Let node be the moved Node, old parent and old index be the old parent
  // (which may be null) and index, and new parent and new index be the new
  // parent and index."
  var oldParent = node.parentNode;
  var oldIndex = getNodeIndex(node);

  // We preserve the global range object, the ranges in the selection, and
  // any range that's in the extraRanges array.  Any other ranges won't get
  // updated, because we have no references to them.
  var ranges = [globalRange].concat(extraRanges);
  for (var i = 0; i < getSelection().rangeCount; i++) {
    ranges.push(getSelection().getRangeAt(i));
  }
  var boundaryPoints = [];
  ranges.forEach(function(range) {
    boundaryPoints.push([range.startContainer, range.startOffset]);
    boundaryPoints.push([range.endContainer, range.endOffset]);
  });

  boundaryPoints.forEach(function(boundaryPoint) {
    // "If a boundary point's node is the same as or a descendant of node,
    // leave it unchanged, so it moves to the new location."
    //
    // No modifications necessary.

    // "If a boundary point's node is new parent and its offset is greater
    // than new index, add one to its offset."
    if (boundaryPoint[0] == newParent
    && boundaryPoint[1] > newIndex) {
      boundaryPoint[1]++;
    }

    // "If a boundary point's node is old parent and its offset is old index or
    // old index + 1, set its node to new parent and add new index − old index
    // to its offset."
    if (boundaryPoint[0] == oldParent
    && (boundaryPoint[1] == oldIndex
    || boundaryPoint[1] == oldIndex + 1)) {
      boundaryPoint[0] = newParent;
      boundaryPoint[1] += newIndex - oldIndex;
    }

    // "If a boundary point's node is old parent and its offset is greater than
    // old index + 1, subtract one from its offset."
    if (boundaryPoint[0] == oldParent
    && boundaryPoint[1] > oldIndex + 1) {
      boundaryPoint[1]--;
    }
  });

  // Now actually move it and preserve the ranges.
  if (newParent.childNodes.length == newIndex) {
    newParent.appendChild(node);
  } else {
    newParent.insertBefore(node, newParent.childNodes[newIndex]);
  }

  globalRange.setStart(boundaryPoints[0][0], boundaryPoints[0][1]);
  globalRange.setEnd(boundaryPoints[1][0], boundaryPoints[1][1]);

  for (var i = 0; i < extraRanges.length; i++) {
    extraRanges[i].setStart(boundaryPoints[2*i + 2][0], boundaryPoints[2*i + 2][1]);
    extraRanges[i].setEnd(boundaryPoints[2*i + 3][0], boundaryPoints[2*i + 3][1]);
  }

  getSelection().removeAllRanges();
  for (var i = 1 + extraRanges.length; i < ranges.length; i++) {
    var newRange = document.createRange();
    newRange.setStart(boundaryPoints[2*i][0], boundaryPoints[2*i][1]);
    newRange.setEnd(boundaryPoints[2*i + 1][0], boundaryPoints[2*i + 1][1]);
    getSelection().addRange(newRange);
  }
}

function setTagName(element, newName) {
  // "If element is an HTML element with local name equal to new name, return
  // element."
  if (isHtmlElement(element, newName.toUpperCase())) {
    return element;
  }

  // "If element's parent is null, return element."
  if (!element.parentNode) {
    return element;
  }

  // "Let replacement element be the result of calling createElement(new
  // name) on the ownerDocument of element."
  var replacementElement = element.ownerDocument.createElement(newName);

  // "Insert replacement element into element's parent immediately before
  // element."
  element.parentNode.insertBefore(replacementElement, element);

  // "Copy all attributes of element to replacement element, in order."
  for (var i = 0; i < element.attributes.length; i++) {
    replacementElement.setAttributeNS(element.attributes[i].namespaceURI, element.attributes[i].name, element.attributes[i].value);
  }

  // "While element has children, append the first child of element as the
  // last child of replacement element, preserving ranges."
  while (element.childNodes.length) {
    movePreservingRanges(element.firstChild, replacementElement, replacementElement.childNodes.length);
  }

  // "Remove element from its parent."
  element.parentNode.removeChild(element);

  // "Return replacement element."
  return replacementElement;
}

function removeExtraneousLineBreaksBefore(node) {
  // "Let ref be the previousSibling of node."
  var ref = node.previousSibling;

  // "If ref is null, abort these steps."
  if (!ref) {
    return;
  }

  // "While ref has children, set ref to its lastChild."
  while (ref.hasChildNodes()) {
    ref = ref.lastChild;
  }

  // "While ref is invisible but not an extraneous line break, and ref does
  // not equal node's parent, set ref to the node before it in tree order."
  while (isInvisible(ref)
  && !isExtraneousLineBreak(ref)
  && ref != node.parentNode) {
    ref = previousNode(ref);
  }

  // "If ref is an editable extraneous line break, remove it from its
  // parent."
  if (isEditable(ref)
  && isExtraneousLineBreak(ref)) {
    ref.parentNode.removeChild(ref);
  }
}

function removeExtraneousLineBreaksAtTheEndOf(node) {
  // "Let ref be node."
  var ref = node;

  // "While ref has children, set ref to its lastChild."
  while (ref.hasChildNodes()) {
    ref = ref.lastChild;
  }

  // "While ref is invisible but not an extraneous line break, and ref does
  // not equal node, set ref to the node before it in tree order."
  while (isInvisible(ref)
  && !isExtraneousLineBreak(ref)
  && ref != node) {
    ref = previousNode(ref);
  }

  // "If ref is an editable extraneous line break:"
  if (isEditable(ref)
  && isExtraneousLineBreak(ref)) {
    // "While ref's parent is editable and invisible, set ref to its
    // parent."
    while (isEditable(ref.parentNode)
    && isInvisible(ref.parentNode)) {
      ref = ref.parentNode;
    }

    // "Remove ref from its parent."
    ref.parentNode.removeChild(ref);
  }
}

// "To remove extraneous line breaks from a node, first remove extraneous line
// breaks before it, then remove extraneous line breaks at the end of it."
function removeExtraneousLineBreaksFrom(node) {
  removeExtraneousLineBreaksBefore(node);
  removeExtraneousLineBreaksAtTheEndOf(node);
}

//@}
///// Wrapping a list of nodes /////
//@{

function wrap(nodeList, siblingCriteria, newParentInstructions) {
  // "If not provided, sibling criteria returns false and new parent
  // instructions returns null."
  if (typeof siblingCriteria == "undefined") {
    siblingCriteria = function() { return false };
  }
  if (typeof newParentInstructions == "undefined") {
    newParentInstructions = function() { return null };
  }

  // "If every member of node list is invisible, and none is a br, return
  // null and abort these steps."
  if (nodeList.every(isInvisible)
  && !nodeList.some(function(node) { return isHtmlElement(node, "br") })) {
    return null;
  }

  // "If node list's first member's parent is null, return null and abort
  // these steps."
  if (!nodeList[0].parentNode) {
    return null;
  }

  // "If node list's last member is an inline node that's not a br, and node
  // list's last member's nextSibling is a br, append that br to node list."
  if (isInlineNode(nodeList[nodeList.length - 1])
  && !isHtmlElement(nodeList[nodeList.length - 1], "br")
  && isHtmlElement(nodeList[nodeList.length - 1].nextSibling, "br")) {
    nodeList.push(nodeList[nodeList.length - 1].nextSibling);
  }

  // "While node list's first member's previousSibling is invisible, prepend
  // it to node list."
  while (isInvisible(nodeList[0].previousSibling)) {
    nodeList.unshift(nodeList[0].previousSibling);
  }

  // "While node list's last member's nextSibling is invisible, append it to
  // node list."
  while (isInvisible(nodeList[nodeList.length - 1].nextSibling)) {
    nodeList.push(nodeList[nodeList.length - 1].nextSibling);
  }

  // "If the previousSibling of the first member of node list is editable and
  // running sibling criteria on it returns true, let new parent be the
  // previousSibling of the first member of node list."
  var newParent;
  if (isEditable(nodeList[0].previousSibling)
  && siblingCriteria(nodeList[0].previousSibling)) {
    newParent = nodeList[0].previousSibling;

  // "Otherwise, if the nextSibling of the last member of node list is
  // editable and running sibling criteria on it returns true, let new parent
  // be the nextSibling of the last member of node list."
  } else if (isEditable(nodeList[nodeList.length - 1].nextSibling)
  && siblingCriteria(nodeList[nodeList.length - 1].nextSibling)) {
    newParent = nodeList[nodeList.length - 1].nextSibling;

  // "Otherwise, run new parent instructions, and let new parent be the
  // result."
  } else {
    newParent = newParentInstructions();
  }

  // "If new parent is null, abort these steps and return null."
  if (!newParent) {
    return null;
  }

  // "If new parent's parent is null:"
  if (!newParent.parentNode) {
    // "Insert new parent into the parent of the first member of node list
    // immediately before the first member of node list."
    nodeList[0].parentNode.insertBefore(newParent, nodeList[0]);

    // "If any range has a boundary point with node equal to the parent of
    // new parent and offset equal to the index of new parent, add one to
    // that boundary point's offset."
    //
    // Only try to fix the global range.
    if (globalRange.startContainer == newParent.parentNode
    && globalRange.startOffset == getNodeIndex(newParent)) {
      globalRange.setStart(globalRange.startContainer, globalRange.startOffset + 1);
    }
    if (globalRange.endContainer == newParent.parentNode
    && globalRange.endOffset == getNodeIndex(newParent)) {
      globalRange.setEnd(globalRange.endContainer, globalRange.endOffset + 1);
    }
  }

  // "Let original parent be the parent of the first member of node list."
  var originalParent = nodeList[0].parentNode;

  // "If new parent is before the first member of node list in tree order:"
  if (isBefore(newParent, nodeList[0])) {
    // "If new parent is not an inline node, but the last visible child of
    // new parent and the first visible member of node list are both inline
    // nodes, and the last child of new parent is not a br, call
    // createElement("br") on the ownerDocument of new parent and append
    // the result as the last child of new parent."
    if (!isInlineNode(newParent)
    && isInlineNode([].filter.call(newParent.childNodes, isVisible).slice(-1)[0])
    && isInlineNode(nodeList.filter(isVisible)[0])
    && !isHtmlElement(newParent.lastChild, "BR")) {
      newParent.appendChild(newParent.ownerDocument.createElement("br"));
    }

    // "For each node in node list, append node as the last child of new
    // parent, preserving ranges."
    for (var i = 0; i < nodeList.length; i++) {
      movePreservingRanges(nodeList[i], newParent, -1);
    }

  // "Otherwise:"
  } else {
    // "If new parent is not an inline node, but the first visible child of
    // new parent and the last visible member of node list are both inline
    // nodes, and the last member of node list is not a br, call
    // createElement("br") on the ownerDocument of new parent and insert
    // the result as the first child of new parent."
    if (!isInlineNode(newParent)
    && isInlineNode([].filter.call(newParent.childNodes, isVisible)[0])
    && isInlineNode(nodeList.filter(isVisible).slice(-1)[0])
    && !isHtmlElement(nodeList[nodeList.length - 1], "BR")) {
      newParent.insertBefore(newParent.ownerDocument.createElement("br"), newParent.firstChild);
    }

    // "For each node in node list, in reverse order, insert node as the
    // first child of new parent, preserving ranges."
    for (var i = nodeList.length - 1; i >= 0; i--) {
      movePreservingRanges(nodeList[i], newParent, 0);
    }
  }

  // "If original parent is editable and has no children, remove it from its
  // parent."
  if (isEditable(originalParent) && !originalParent.hasChildNodes()) {
    originalParent.parentNode.removeChild(originalParent);
  }

  // "If new parent's nextSibling is editable and running sibling criteria on
  // it returns true:"
  if (isEditable(newParent.nextSibling)
  && siblingCriteria(newParent.nextSibling)) {
    // "If new parent is not an inline node, but new parent's last child
    // and new parent's nextSibling's first child are both inline nodes,
    // and new parent's last child is not a br, call createElement("br") on
    // the ownerDocument of new parent and append the result as the last
    // child of new parent."
    if (!isInlineNode(newParent)
    && isInlineNode(newParent.lastChild)
    && isInlineNode(newParent.nextSibling.firstChild)
    && !isHtmlElement(newParent.lastChild, "BR")) {
      newParent.appendChild(newParent.ownerDocument.createElement("br"));
    }

    // "While new parent's nextSibling has children, append its first child
    // as the last child of new parent, preserving ranges."
    while (newParent.nextSibling.hasChildNodes()) {
      movePreservingRanges(newParent.nextSibling.firstChild, newParent, -1);
    }

    // "Remove new parent's nextSibling from its parent."
    newParent.parentNode.removeChild(newParent.nextSibling);
  }

  // "Remove extraneous line breaks from new parent."
  removeExtraneousLineBreaksFrom(newParent);

  // "Return new parent."
  return newParent;
}


//@}
///// Allowed children /////
//@{

// "A name of an element with inline contents is "a", "abbr", "b", "bdi",
// "bdo", "cite", "code", "dfn", "em", "h1", "h2", "h3", "h4", "h5", "h6", "i",
// "kbd", "mark", "p", "pre", "q", "rp", "rt", "ruby", "s", "samp", "small",
// "span", "strong", "sub", "sup", "u", "var", "acronym", "listing", "strike",
// "xmp", "big", "blink", "font", "marquee", "nobr", or "tt"."
var namesOfElementsWithInlineContents = ["a", "abbr", "b", "bdi", "bdo",
  "cite", "code", "dfn", "em", "h1", "h2", "h3", "h4", "h5", "h6", "i",
  "kbd", "mark", "p", "pre", "q", "rp", "rt", "ruby", "s", "samp", "small",
  "span", "strong", "sub", "sup", "u", "var", "acronym", "listing", "strike",
  "xmp", "big", "blink", "font", "marquee", "nobr", "tt"];

// "An element with inline contents is an HTML element whose local name is a
// name of an element with inline contents."
function isElementWithInlineContents(node) {
  return isHtmlElement(node, namesOfElementsWithInlineContents);
}

function isAllowedChild(child, parent_) {
  // "If parent is "colgroup", "table", "tbody", "tfoot", "thead", "tr", or
  // an HTML element with local name equal to one of those, and child is a
  // Text node whose data does not consist solely of space characters, return
  // false."
  if ((["colgroup", "table", "tbody", "tfoot", "thead", "tr"].indexOf(parent_) != -1
  || isHtmlElement(parent_, ["colgroup", "table", "tbody", "tfoot", "thead", "tr"]))
  && typeof child == "object"
  && child.nodeType == Node.TEXT_NODE
  && !/^[ \t\n\f\r]*$/.test(child.data)) {
    return false;
  }

  // "If parent is "script", "style", "plaintext", or "xmp", or an HTML
  // element with local name equal to one of those, and child is not a Text
  // node, return false."
  if ((["script", "style", "plaintext", "xmp"].indexOf(parent_) != -1
  || isHtmlElement(parent_, ["script", "style", "plaintext", "xmp"]))
  && (typeof child != "object" || child.nodeType != Node.TEXT_NODE)) {
    return false;
  }

  // "If child is a Document, DocumentFragment, or DocumentType, return
  // false."
  if (typeof child == "object"
  && (child.nodeType == Node.DOCUMENT_NODE
  || child.nodeType == Node.DOCUMENT_FRAGMENT_NODE
  || child.nodeType == Node.DOCUMENT_TYPE_NODE)) {
    return false;
  }

  // "If child is an HTML element, set child to the local name of child."
  if (isHtmlElement(child)) {
    child = child.tagName.toLowerCase();
  }

  // "If child is not a string, return true."
  if (typeof child != "string") {
    return true;
  }

  // "If parent is an HTML element:"
  if (isHtmlElement(parent_)) {
    // "If child is "a", and parent or some ancestor of parent is an a,
    // return false."
    //
    // "If child is a prohibited paragraph child name and parent or some
    // ancestor of parent is an element with inline contents, return
    // false."
    //
    // "If child is "h1", "h2", "h3", "h4", "h5", or "h6", and parent or
    // some ancestor of parent is an HTML element with local name "h1",
    // "h2", "h3", "h4", "h5", or "h6", return false."
    var ancestor = parent_;
    while (ancestor) {
      if (child == "a" && isHtmlElement(ancestor, "a")) {
        return false;
      }
      if (prohibitedParagraphChildNames.indexOf(child) != -1
      && isElementWithInlineContents(ancestor)) {
        return false;
      }
      if (/^h[1-6]$/.test(child)
      && isHtmlElement(ancestor)
      && /^H[1-6]$/.test(ancestor.tagName)) {
        return false;
      }
      ancestor = ancestor.parentNode;
    }

    // "Let parent be the local name of parent."
    parent_ = parent_.tagName.toLowerCase();
  }

  // "If parent is an Element or DocumentFragment, return true."
  if (typeof parent_ == "object"
  && (parent_.nodeType == Node.ELEMENT_NODE
  || parent_.nodeType == Node.DOCUMENT_FRAGMENT_NODE)) {
    return true;
  }

  // "If parent is not a string, return false."
  if (typeof parent_ != "string") {
    return false;
  }

  // "If parent is on the left-hand side of an entry on the following list,
  // then return true if child is listed on the right-hand side of that
  // entry, and false otherwise."
  switch (parent_) {
    case "colgroup":
      return child == "col";
    case "table":
      return ["caption", "col", "colgroup", "tbody", "td", "tfoot", "th", "thead", "tr"].indexOf(child) != -1;
    case "tbody":
    case "thead":
    case "tfoot":
      return ["td", "th", "tr"].indexOf(child) != -1;
    case "tr":
      return ["td", "th"].indexOf(child) != -1;
    case "dl":
      return ["dt", "dd"].indexOf(child) != -1;
    case "dir":
    case "ol":
    case "ul":
      return ["dir", "li", "ol", "ul"].indexOf(child) != -1;
    case "hgroup":
      return /^h[1-6]$/.test(child);
  }

  // "If child is "body", "caption", "col", "colgroup", "frame", "frameset",
  // "head", "html", "tbody", "td", "tfoot", "th", "thead", or "tr", return
  // false."
  if (["body", "caption", "col", "colgroup", "frame", "frameset", "head",
  "html", "tbody", "td", "tfoot", "th", "thead", "tr"].indexOf(child) != -1) {
    return false;
  }

  // "If child is "dd" or "dt" and parent is not "dl", return false."
  if (["dd", "dt"].indexOf(child) != -1
  && parent_ != "dl") {
    return false;
  }

  // "If child is "li" and parent is not "ol" or "ul", return false."
  if (child == "li"
  && parent_ != "ol"
  && parent_ != "ul") {
    return false;
  }

  // "If parent is on the left-hand side of an entry on the following list
  // and child is listed on the right-hand side of that entry, return false."
  var table = [
    [["a"], ["a"]],
    [["dd", "dt"], ["dd", "dt"]],
    [["h1", "h2", "h3", "h4", "h5", "h6"], ["h1", "h2", "h3", "h4", "h5", "h6"]],
    [["li"], ["li"]],
    [["nobr"], ["nobr"]],
    [namesOfElementsWithInlineContents, prohibitedParagraphChildNames],
    [["td", "th"], ["caption", "col", "colgroup", "tbody", "td", "tfoot", "th", "thead", "tr"]],
  ];
  for (var i = 0; i < table.length; i++) {
    if (table[i][0].indexOf(parent_) != -1
    && table[i][1].indexOf(child) != -1) {
      return false;
    }
  }

  // "Return true."
  return true;
}


//@}

//////////////////////////////////////
///// Inline formatting commands /////
//////////////////////////////////////

///// Inline formatting command definitions /////
//@{

// "A node node is effectively contained in a range range if range is not
// collapsed, and at least one of the following holds:"
function isEffectivelyContained(node, range) {
  if (range.collapsed) {
    return false;
  }

  // "node is contained in range."
  if (isContained(node, range)) {
    return true;
  }

  // "node is range's start node, it is a Text node, and its length is
  // different from range's start offset."
  if (node == range.startContainer
  && node.nodeType == Node.TEXT_NODE
  && getNodeLength(node) != range.startOffset) {
    return true;
  }

  // "node is range's end node, it is a Text node, and range's end offset is
  // not 0."
  if (node == range.endContainer
  && node.nodeType == Node.TEXT_NODE
  && range.endOffset != 0) {
    return true;
  }

  // "node has at least one child; and all its children are effectively
  // contained in range; and either range's start node is not a descendant of
  // node or is not a Text node or range's start offset is zero; and either
  // range's end node is not a descendant of node or is not a Text node or
  // range's end offset is its end node's length."
  if (node.hasChildNodes()
  && [].every.call(node.childNodes, function(child) { return isEffectivelyContained(child, range) })
  && (!isDescendant(range.startContainer, node)
  || range.startContainer.nodeType != Node.TEXT_NODE
  || range.startOffset == 0)
  && (!isDescendant(range.endContainer, node)
  || range.endContainer.nodeType != Node.TEXT_NODE
  || range.endOffset == getNodeLength(range.endContainer))) {
    return true;
  }

  return false;
}

// Like get(All)ContainedNodes(), but for effectively contained nodes.
function getEffectivelyContainedNodes(range, condition) {
  if (typeof condition == "undefined") {
    condition = function() { return true };
  }
  var node = range.startContainer;
  while (isEffectivelyContained(node.parentNode, range)) {
    node = node.parentNode;
  }

  var stop = nextNodeDescendants(range.endContainer);

  var nodeList = [];
  while (isBefore(node, stop)) {
    if (isEffectivelyContained(node, range)
    && condition(node)) {
      nodeList.push(node);
      node = nextNodeDescendants(node);
      continue;
    }
    node = nextNode(node);
  }
  return nodeList;
}

function getAllEffectivelyContainedNodes(range, condition) {
  if (typeof condition == "undefined") {
    condition = function() { return true };
  }
  var node = range.startContainer;
  while (isEffectivelyContained(node.parentNode, range)) {
    node = node.parentNode;
  }

  var stop = nextNodeDescendants(range.endContainer);

  var nodeList = [];
  while (isBefore(node, stop)) {
    if (isEffectivelyContained(node, range)
    && condition(node)) {
      nodeList.push(node);
    }
    node = nextNode(node);
  }
  return nodeList;
}

// "A modifiable element is a b, em, i, s, span, strong, sub, sup, or u element
// with no attributes except possibly style; or a font element with no
// attributes except possibly style, color, face, and/or size; or an a element
// with no attributes except possibly style and/or href."
function isModifiableElement(node) {
  if (!isHtmlElement(node)) {
    return false;
  }

  if (["B", "EM", "I", "S", "SPAN", "STRIKE", "STRONG", "SUB", "SUP", "U"].indexOf(node.tagName) != -1) {
    if (node.attributes.length == 0) {
      return true;
    }

    if (node.attributes.length == 1
    && node.hasAttribute("style")) {
      return true;
    }
  }

  if (node.tagName == "FONT" || node.tagName == "A") {
    var numAttrs = node.attributes.length;

    if (node.hasAttribute("style")) {
      numAttrs--;
    }

    if (node.tagName == "FONT") {
      if (node.hasAttribute("color")) {
        numAttrs--;
      }

      if (node.hasAttribute("face")) {
        numAttrs--;
      }

      if (node.hasAttribute("size")) {
        numAttrs--;
      }
    }

    if (node.tagName == "A"
    && node.hasAttribute("href")) {
      numAttrs--;
    }

    if (numAttrs == 0) {
      return true;
    }
  }

  return false;
}

function isSimpleModifiableElement(node) {
  // "A simple modifiable element is an HTML element for which at least one
  // of the following holds:"
  if (!isHtmlElement(node)) {
    return false;
  }

  // Only these elements can possibly be a simple modifiable element.
  if (["A", "B", "EM", "FONT", "I", "S", "SPAN", "STRIKE", "STRONG", "SUB", "SUP", "U"].indexOf(node.tagName) == -1) {
    return false;
  }

  // "It is an a, b, em, font, i, s, span, strike, strong, sub, sup, or u
  // element with no attributes."
  if (node.attributes.length == 0) {
    return true;
  }

  // If it's got more than one attribute, everything after this fails.
  if (node.attributes.length > 1) {
    return false;
  }

  // "It is an a, b, em, font, i, s, span, strike, strong, sub, sup, or u
  // element with exactly one attribute, which is style, which sets no CSS
  // properties (including invalid or unrecognized properties)."
  //
  // Not gonna try for invalid or unrecognized.
  if (node.hasAttribute("style")
  && node.style.length == 0) {
    return true;
  }

  // "It is an a element with exactly one attribute, which is href."
  if (node.tagName == "A"
  && node.hasAttribute("href")) {
    return true;
  }

  // "It is a font element with exactly one attribute, which is either color,
  // face, or size."
  if (node.tagName == "FONT"
  && (node.hasAttribute("color")
  || node.hasAttribute("face")
  || node.hasAttribute("size")
  )) {
    return true;
  }

  // "It is a b or strong element with exactly one attribute, which is style,
  // and the style attribute sets exactly one CSS property (including invalid
  // or unrecognized properties), which is "font-weight"."
  if ((node.tagName == "B" || node.tagName == "STRONG")
  && node.hasAttribute("style")
  && node.style.length == 1
  && node.style.fontWeight != "") {
    return true;
  }

  // "It is an i or em element with exactly one attribute, which is style,
  // and the style attribute sets exactly one CSS property (including invalid
  // or unrecognized properties), which is "font-style"."
  if ((node.tagName == "I" || node.tagName == "EM")
  && node.hasAttribute("style")
  && node.style.length == 1
  && node.style.fontStyle != "") {
    return true;
  }

  // "It is an a, font, or span element with exactly one attribute, which is
  // style, and the style attribute sets exactly one CSS property (including
  // invalid or unrecognized properties), and that property is not
  // "text-decoration"."
  if ((node.tagName == "A" || node.tagName == "FONT" || node.tagName == "SPAN")
  && node.hasAttribute("style")
  && node.style.length == 1
  && node.style.textDecoration == "") {
    return true;
  }

  // "It is an a, font, s, span, strike, or u element with exactly one
  // attribute, which is style, and the style attribute sets exactly one CSS
  // property (including invalid or unrecognized properties), which is
  // "text-decoration", which is set to "line-through" or "underline" or
  // "overline" or "none"."
  //
  // The weird extra node.style.length check is for Firefox, which as of
  // 8.0a2 has annoying and weird behavior here.
  if (["A", "FONT", "S", "SPAN", "STRIKE", "U"].indexOf(node.tagName) != -1
  && node.hasAttribute("style")
  && (node.style.length == 1
  || (node.style.length == 4
    && "MozTextBlink" in node.style
    && "MozTextDecorationColor" in node.style
    && "MozTextDecorationLine" in node.style
    && "MozTextDecorationStyle" in node.style)
  )
  && (node.style.textDecoration == "line-through"
  || node.style.textDecoration == "underline"
  || node.style.textDecoration == "overline"
  || node.style.textDecoration == "none")) {
    return true;
  }

  return false;
}

// "A formattable node is an editable visible node that is either a Text node,
// an img, or a br."
function isFormattableNode(node) {
  return isEditable(node)
    && isVisible(node)
    && (node.nodeType == Node.TEXT_NODE
    || isHtmlElement(node, ["img", "br"]));
}

// "Two quantities are equivalent values for a command if either both are null,
// or both are strings and they're equal and the command does not define any
// equivalent values, or both are strings and the command defines equivalent
// values and they match the definition."
function areEquivalentValues(command, val1, val2) {
  if (val1 === null && val2 === null) {
    return true;
  }

  if (typeof val1 == "string"
  && typeof val2 == "string"
  && val1 == val2
  && !("equivalentValues" in commands[command])) {
    return true;
  }

  if (typeof val1 == "string"
  && typeof val2 == "string"
  && "equivalentValues" in commands[command]
  && commands[command].equivalentValues(val1, val2)) {
    return true;
  }

  return false;
}

// "Two quantities are loosely equivalent values for a command if either they
// are equivalent values for the command, or if the command is the fontSize
// command; one of the quantities is one of "x-small", "small", "medium",
// "large", "x-large", "xx-large", or "xxx-large"; and the other quantity is
// the resolved value of "font-size" on a font element whose size attribute has
// the corresponding value set ("1" through "7" respectively)."
function areLooselyEquivalentValues(command, val1, val2) {
  if (areEquivalentValues(command, val1, val2)) {
    return true;
  }

  if (command != "fontsize"
  || typeof val1 != "string"
  || typeof val2 != "string") {
    return false;
  }

  // Static variables in JavaScript?
  var callee = areLooselyEquivalentValues;
  if (callee.sizeMap === undefined) {
    callee.sizeMap = {};
    var font = document.createElement("font");
    document.body.appendChild(font);
    ["x-small", "small", "medium", "large", "x-large", "xx-large",
    "xxx-large"].forEach(function(keyword) {
      font.size = cssSizeToLegacy(keyword);
      callee.sizeMap[keyword] = getComputedStyle(font).fontSize;
    });
    document.body.removeChild(font);
  }

  return val1 === callee.sizeMap[val2]
    || val2 === callee.sizeMap[val1];
}

//@}
///// Assorted inline formatting command algorithms /////
//@{

function getEffectiveCommandValue(node, command) {
  // "If neither node nor its parent is an Element, return null."
  if (node.nodeType != Node.ELEMENT_NODE
  && (!node.parentNode || node.parentNode.nodeType != Node.ELEMENT_NODE)) {
    return null;
  }

  // "If node is not an Element, return the effective command value of its
  // parent for command."
  if (node.nodeType != Node.ELEMENT_NODE) {
    return getEffectiveCommandValue(node.parentNode, command);
  }

  // "If command is "createLink" or "unlink":"
  if (command == "createlink" || command == "unlink") {
    // "While node is not null, and is not an a element that has an href
    // attribute, set node to its parent."
    while (node
    && (!isHtmlElement(node)
    || node.tagName != "A"
    || !node.hasAttribute("href"))) {
      node = node.parentNode;
    }

    // "If node is null, return null."
    if (!node) {
      return null;
    }

    // "Return the value of node's href attribute."
    return node.getAttribute("href");
  }

  // "If command is "backColor" or "hiliteColor":"
  if (command == "backcolor"
  || command == "hilitecolor") {
    // "While the resolved value of "background-color" on node is any
    // fully transparent value, and node's parent is an Element, set
    // node to its parent."
    //
    // Another lame hack to avoid flawed APIs.
    while ((getComputedStyle(node).backgroundColor == "rgba(0, 0, 0, 0)"
    || getComputedStyle(node).backgroundColor === ""
    || getComputedStyle(node).backgroundColor == "transparent")
    && node.parentNode
    && node.parentNode.nodeType == Node.ELEMENT_NODE) {
      node = node.parentNode;
    }

    // "Return the resolved value of "background-color" for node."
    return getComputedStyle(node).backgroundColor;
  }

  // "If command is "subscript" or "superscript":"
  if (command == "subscript" || command == "superscript") {
    // "Let affected by subscript and affected by superscript be two
    // boolean variables, both initially false."
    var affectedBySubscript = false;
    var affectedBySuperscript = false;

    // "While node is an inline node:"
    while (isInlineNode(node)) {
      var verticalAlign = getComputedStyle(node).verticalAlign;

      // "If node is a sub, set affected by subscript to true."
      if (isHtmlElement(node, "sub")) {
        affectedBySubscript = true;
      // "Otherwise, if node is a sup, set affected by superscript to
      // true."
      } else if (isHtmlElement(node, "sup")) {
        affectedBySuperscript = true;
      }

      // "Set node to its parent."
      node = node.parentNode;
    }

    // "If affected by subscript and affected by superscript are both true,
    // return the string "mixed"."
    if (affectedBySubscript && affectedBySuperscript) {
      return "mixed";
    }

    // "If affected by subscript is true, return "subscript"."
    if (affectedBySubscript) {
      return "subscript";
    }

    // "If affected by superscript is true, return "superscript"."
    if (affectedBySuperscript) {
      return "superscript";
    }

    // "Return null."
    return null;
  }

  // "If command is "strikethrough", and the "text-decoration" property of
  // node or any of its ancestors has resolved value containing
  // "line-through", return "line-through". Otherwise, return null."
  if (command == "strikethrough") {
    do {
      if (getComputedStyle(node).textDecoration.indexOf("line-through") != -1) {
        return "line-through";
      }
      node = node.parentNode;
    } while (node && node.nodeType == Node.ELEMENT_NODE);
    return null;
  }

  // "If command is "underline", and the "text-decoration" property of node
  // or any of its ancestors has resolved value containing "underline",
  // return "underline". Otherwise, return null."
  if (command == "underline") {
    do {
      if (getComputedStyle(node).textDecoration.indexOf("underline") != -1) {
        return "underline";
      }
      node = node.parentNode;
    } while (node && node.nodeType == Node.ELEMENT_NODE);
    return null;
  }

  if (!("relevantCssProperty" in commands[command])) {
    throw "Bug: no relevantCssProperty for " + command + " in getEffectiveCommandValue";
  }

  // "Return the resolved value for node of the relevant CSS property for
  // command."
  return getComputedStyle(node)[commands[command].relevantCssProperty];
}

function getSpecifiedCommandValue(element, command) {
  // "If command is "backColor" or "hiliteColor" and element's display
  // property does not have resolved value "inline", return null."
  if ((command == "backcolor" || command == "hilitecolor")
  && getComputedStyle(element).display != "inline") {
    return null;
  }

  // "If command is "createLink" or "unlink":"
  if (command == "createlink" || command == "unlink") {
    // "If element is an a element and has an href attribute, return the
    // value of that attribute."
    if (isHtmlElement(element)
    && element.tagName == "A"
    && element.hasAttribute("href")) {
      return element.getAttribute("href");
    }

    // "Return null."
    return null;
  }

  // "If command is "subscript" or "superscript":"
  if (command == "subscript" || command == "superscript") {
    // "If element is a sup, return "superscript"."
    if (isHtmlElement(element, "sup")) {
      return "superscript";
    }

    // "If element is a sub, return "subscript"."
    if (isHtmlElement(element, "sub")) {
      return "subscript";
    }

    // "Return null."
    return null;
  }

  // "If command is "strikethrough", and element has a style attribute set,
  // and that attribute sets "text-decoration":"
  if (command == "strikethrough"
  && element.style.textDecoration != "") {
    // "If element's style attribute sets "text-decoration" to a value
    // containing "line-through", return "line-through"."
    if (element.style.textDecoration.indexOf("line-through") != -1) {
      return "line-through";
    }

    // "Return null."
    return null;
  }

  // "If command is "strikethrough" and element is a s or strike element,
  // return "line-through"."
  if (command == "strikethrough"
  && isHtmlElement(element, ["S", "STRIKE"])) {
    return "line-through";
  }

  // "If command is "underline", and element has a style attribute set, and
  // that attribute sets "text-decoration":"
  if (command == "underline"
  && element.style.textDecoration != "") {
    // "If element's style attribute sets "text-decoration" to a value
    // containing "underline", return "underline"."
    if (element.style.textDecoration.indexOf("underline") != -1) {
      return "underline";
    }

    // "Return null."
    return null;
  }

  // "If command is "underline" and element is a u element, return
  // "underline"."
  if (command == "underline"
  && isHtmlElement(element, "U")) {
    return "underline";
  }

  // "Let property be the relevant CSS property for command."
  var property = commands[command].relevantCssProperty;

  // "If property is null, return null."
  if (property === null) {
    return null;
  }

  // "If element has a style attribute set, and that attribute has the
  // effect of setting property, return the value that it sets property to."
  if (element.style[property] != "") {
    return element.style[property];
  }

  // "If element is a font element that has an attribute whose effect is
  // to create a presentational hint for property, return the value that the
  // hint sets property to.  (For a size of 7, this will be the non-CSS value
  // "xxx-large".)"
  if (isHtmlNamespace(element.namespaceURI)
  && element.tagName == "FONT") {
    if (property == "color" && element.hasAttribute("color")) {
      return element.color;
    }
    if (property == "fontFamily" && element.hasAttribute("face")) {
      return element.face;
    }
    if (property == "fontSize" && element.hasAttribute("size")) {
      // This is not even close to correct in general.
      var size = parseInt(element.size);
      if (size < 1) {
        size = 1;
      }
      if (size > 7) {
        size = 7;
      }
      return {
        1: "x-small",
        2: "small",
        3: "medium",
        4: "large",
        5: "x-large",
        6: "xx-large",
        7: "xxx-large"
      }[size];
    }
  }

  // "If element is in the following list, and property is equal to the
  // CSS property name listed for it, return the string listed for it."
  //
  // A list follows, whose meaning is copied here.
  if (property == "fontWeight"
  && (element.tagName == "B" || element.tagName == "STRONG")) {
    return "bold";
  }
  if (property == "fontStyle"
  && (element.tagName == "I" || element.tagName == "EM")) {
    return "italic";
  }

  // "Return null."
  return null;
}

function reorderModifiableDescendants(node, command, newValue) {
  // "Let candidate equal node."
  var candidate = node;

  // "While candidate is a modifiable element, and candidate has exactly one
  // child, and that child is also a modifiable element, and candidate is not
  // a simple modifiable element or candidate's specified command value for
  // command is not equivalent to new value, set candidate to its child."
  while (isModifiableElement(candidate)
  && candidate.childNodes.length == 1
  && isModifiableElement(candidate.firstChild)
  && (!isSimpleModifiableElement(candidate)
  || !areEquivalentValues(command, getSpecifiedCommandValue(candidate, command), newValue))) {
    candidate = candidate.firstChild;
  }

  // "If candidate is node, or is not a simple modifiable element, or its
  // specified command value is not equivalent to new value, or its effective
  // command value is not loosely equivalent to new value, abort these
  // steps."
  if (candidate == node
  || !isSimpleModifiableElement(candidate)
  || !areEquivalentValues(command, getSpecifiedCommandValue(candidate, command), newValue)
  || !areLooselyEquivalentValues(command, getEffectiveCommandValue(candidate, command), newValue)) {
    return;
  }

  // "While candidate has children, insert the first child of candidate into
  // candidate's parent immediately before candidate, preserving ranges."
  while (candidate.hasChildNodes()) {
    movePreservingRanges(candidate.firstChild, candidate.parentNode, getNodeIndex(candidate));
  }

  // "Insert candidate into node's parent immediately after node."
  node.parentNode.insertBefore(candidate, node.nextSibling);

  // "Append the node as the last child of candidate, preserving ranges."
  movePreservingRanges(node, candidate, -1);
}

function recordValues(nodeList) {
  // "Let values be a list of (node, command, specified command value)
  // triples, initially empty."
  var values = [];

  // "For each node in node list, for each command in the list "subscript",
  // "bold", "fontName", "fontSize", "foreColor", "hiliteColor", "italic",
  // "strikethrough", and "underline" in that order:"
  nodeList.forEach(function(node) {
    ["subscript", "bold", "fontname", "fontsize", "forecolor",
    "hilitecolor", "italic", "strikethrough", "underline"].forEach(function(command) {
      // "Let ancestor equal node."
      var ancestor = node;

      // "If ancestor is not an Element, set it to its parent."
      if (ancestor.nodeType != Node.ELEMENT_NODE) {
        ancestor = ancestor.parentNode;
      }

      // "While ancestor is an Element and its specified command value
      // for command is null, set it to its parent."
      while (ancestor
      && ancestor.nodeType == Node.ELEMENT_NODE
      && getSpecifiedCommandValue(ancestor, command) === null) {
        ancestor = ancestor.parentNode;
      }

      // "If ancestor is an Element, add (node, command, ancestor's
      // specified command value for command) to values. Otherwise add
      // (node, command, null) to values."
      if (ancestor && ancestor.nodeType == Node.ELEMENT_NODE) {
        values.push([node, command, getSpecifiedCommandValue(ancestor, command)]);
      } else {
        values.push([node, command, null]);
      }
    });
  });

  // "Return values."
  return values;
}

function restoreValues(values) {
  // "For each (node, command, value) triple in values:"
  values.forEach(function(triple) {
    var node = triple[0];
    var command = triple[1];
    var value = triple[2];

    // "Let ancestor equal node."
    var ancestor = node;

    // "If ancestor is not an Element, set it to its parent."
    if (!ancestor || ancestor.nodeType != Node.ELEMENT_NODE) {
      ancestor = ancestor.parentNode;
    }

    // "While ancestor is an Element and its specified command value for
    // command is null, set it to its parent."
    while (ancestor
    && ancestor.nodeType == Node.ELEMENT_NODE
    && getSpecifiedCommandValue(ancestor, command) === null) {
      ancestor = ancestor.parentNode;
    }

    // "If value is null and ancestor is an Element, push down values on
    // node for command, with new value null."
    if (value === null
    && ancestor
    && ancestor.nodeType == Node.ELEMENT_NODE) {
      pushDownValues(node, command, null);

    // "Otherwise, if ancestor is an Element and its specified command
    // value for command is not equivalent to value, or if ancestor is not
    // an Element and value is not null, force the value of command to
    // value on node."
    } else if ((ancestor
    && ancestor.nodeType == Node.ELEMENT_NODE
    && !areEquivalentValues(command, getSpecifiedCommandValue(ancestor, command), value))
    || ((!ancestor || ancestor.nodeType != Node.ELEMENT_NODE)
    && value !== null)) {
      forceValue(node, command, value);
    }
  });
}


//@}
///// Clearing an element's value /////
//@{

function clearValue(element, command) {
  // "If element is not editable, return the empty list."
  if (!isEditable(element)) {
    return [];
  }

  // "If element's specified command value for command is null, return the
  // empty list."
  if (getSpecifiedCommandValue(element, command) === null) {
    return [];
  }

  // "If element is a simple modifiable element:"
  if (isSimpleModifiableElement(element)) {
    // "Let children be the children of element."
    var children = Array.prototype.slice.call(element.childNodes);

    // "For each child in children, insert child into element's parent
    // immediately before element, preserving ranges."
    for (var i = 0; i < children.length; i++) {
      movePreservingRanges(children[i], element.parentNode, getNodeIndex(element));
    }

    // "Remove element from its parent."
    element.parentNode.removeChild(element);

    // "Return children."
    return children;
  }

  // "If command is "strikethrough", and element has a style attribute that
  // sets "text-decoration" to some value containing "line-through", delete
  // "line-through" from the value."
  if (command == "strikethrough"
  && element.style.textDecoration.indexOf("line-through") != -1) {
    if (element.style.textDecoration == "line-through") {
      element.style.textDecoration = "";
    } else {
      element.style.textDecoration = element.style.textDecoration.replace("line-through", "");
    }
    if (element.getAttribute("style") == "") {
      element.removeAttribute("style");
    }
  }

  // "If command is "underline", and element has a style attribute that sets
  // "text-decoration" to some value containing "underline", delete
  // "underline" from the value."
  if (command == "underline"
  && element.style.textDecoration.indexOf("underline") != -1) {
    if (element.style.textDecoration == "underline") {
      element.style.textDecoration = "";
    } else {
      element.style.textDecoration = element.style.textDecoration.replace("underline", "");
    }
    if (element.getAttribute("style") == "") {
      element.removeAttribute("style");
    }
  }

  // "If the relevant CSS property for command is not null, unset the CSS
  // property property of element."
  if (commands[command].relevantCssProperty !== null) {
    element.style[commands[command].relevantCssProperty] = '';
    if (element.getAttribute("style") == "") {
      element.removeAttribute("style");
    }
  }

  // "If element is a font element:"
  if (isHtmlNamespace(element.namespaceURI) && element.tagName == "FONT") {
    // "If command is "foreColor", unset element's color attribute, if set."
    if (command == "forecolor") {
      element.removeAttribute("color");
    }

    // "If command is "fontName", unset element's face attribute, if set."
    if (command == "fontname") {
      element.removeAttribute("face");
    }

    // "If command is "fontSize", unset element's size attribute, if set."
    if (command == "fontsize") {
      element.removeAttribute("size");
    }
  }

  // "If element is an a element and command is "createLink" or "unlink",
  // unset the href property of element."
  if (isHtmlElement(element, "A")
  && (command == "createlink" || command == "unlink")) {
    element.removeAttribute("href");
  }

  // "If element's specified command value for command is null, return the
  // empty list."
  if (getSpecifiedCommandValue(element, command) === null) {
    return [];
  }

  // "Set the tag name of element to "span", and return the one-node list
  // consisting of the result."
  return [setTagName(element, "span")];
}


//@}
///// Pushing down values /////
//@{

function pushDownValues(node, command, newValue) {
  // "If node's parent is not an Element, abort this algorithm."
  if (!node.parentNode
  || node.parentNode.nodeType != Node.ELEMENT_NODE) {
    return;
  }

  // "If the effective command value of command is loosely equivalent to new
  // value on node, abort this algorithm."
  if (areLooselyEquivalentValues(command, getEffectiveCommandValue(node, command), newValue)) {
    return;
  }

  // "Let current ancestor be node's parent."
  var currentAncestor = node.parentNode;

  // "Let ancestor list be a list of Nodes, initially empty."
  var ancestorList = [];

  // "While current ancestor is an editable Element and the effective command
  // value of command is not loosely equivalent to new value on it, append
  // current ancestor to ancestor list, then set current ancestor to its
  // parent."
  while (isEditable(currentAncestor)
  && currentAncestor.nodeType == Node.ELEMENT_NODE
  && !areLooselyEquivalentValues(command, getEffectiveCommandValue(currentAncestor, command), newValue)) {
    ancestorList.push(currentAncestor);
    currentAncestor = currentAncestor.parentNode;
  }

  // "If ancestor list is empty, abort this algorithm."
  if (!ancestorList.length) {
    return;
  }

  // "Let propagated value be the specified command value of command on the
  // last member of ancestor list."
  var propagatedValue = getSpecifiedCommandValue(ancestorList[ancestorList.length - 1], command);

  // "If propagated value is null and is not equal to new value, abort this
  // algorithm."
  if (propagatedValue === null && propagatedValue != newValue) {
    return;
  }

  // "If the effective command value for the parent of the last member of
  // ancestor list is not loosely equivalent to new value, and new value is
  // not null, abort this algorithm."
  if (newValue !== null
  && !areLooselyEquivalentValues(command, getEffectiveCommandValue(ancestorList[ancestorList.length - 1].parentNode, command), newValue)) {
    return;
  }

  // "While ancestor list is not empty:"
  while (ancestorList.length) {
    // "Let current ancestor be the last member of ancestor list."
    // "Remove the last member from ancestor list."
    var currentAncestor = ancestorList.pop();

    // "If the specified command value of current ancestor for command is
    // not null, set propagated value to that value."
    if (getSpecifiedCommandValue(currentAncestor, command) !== null) {
      propagatedValue = getSpecifiedCommandValue(currentAncestor, command);
    }

    // "Let children be the children of current ancestor."
    var children = Array.prototype.slice.call(currentAncestor.childNodes);

    // "If the specified command value of current ancestor for command is
    // not null, clear the value of current ancestor."
    if (getSpecifiedCommandValue(currentAncestor, command) !== null) {
      clearValue(currentAncestor, command);
    }

    // "For every child in children:"
    for (var i = 0; i < children.length; i++) {
      var child = children[i];

      // "If child is node, continue with the next child."
      if (child == node) {
        continue;
      }

      // "If child is an Element whose specified command value for
      // command is neither null nor equivalent to propagated value,
      // continue with the next child."
      if (child.nodeType == Node.ELEMENT_NODE
      && getSpecifiedCommandValue(child, command) !== null
      && !areEquivalentValues(command, propagatedValue, getSpecifiedCommandValue(child, command))) {
        continue;
      }

      // "If child is the last member of ancestor list, continue with the
      // next child."
      if (child == ancestorList[ancestorList.length - 1]) {
        continue;
      }

      // "Force the value of child, with command as in this algorithm
      // and new value equal to propagated value."
      forceValue(child, command, propagatedValue);
    }
  }
}


//@}
///// Forcing the value of a node /////
//@{

function forceValue(node, command, newValue) {
  // "If node's parent is null, abort this algorithm."
  if (!node.parentNode) {
    return;
  }

  // "If new value is null, abort this algorithm."
  if (newValue === null) {
    return;
  }

  // "If node is an allowed child of "span":"
  if (isAllowedChild(node, "span")) {
    // "Reorder modifiable descendants of node's previousSibling."
    reorderModifiableDescendants(node.previousSibling, command, newValue);

    // "Reorder modifiable descendants of node's nextSibling."
    reorderModifiableDescendants(node.nextSibling, command, newValue);

    // "Wrap the one-node list consisting of node, with sibling criteria
    // returning true for a simple modifiable element whose specified
    // command value is equivalent to new value and whose effective command
    // value is loosely equivalent to new value and false otherwise, and
    // with new parent instructions returning null."
    wrap([node],
      function(node) {
        return isSimpleModifiableElement(node)
          && areEquivalentValues(command, getSpecifiedCommandValue(node, command), newValue)
          && areLooselyEquivalentValues(command, getEffectiveCommandValue(node, command), newValue);
      },
      function() { return null }
    );
  }

  // "If node is invisible, abort this algorithm."
  if (isInvisible(node)) {
    return;
  }

  // "If the effective command value of command is loosely equivalent to new
  // value on node, abort this algorithm."
  if (areLooselyEquivalentValues(command, getEffectiveCommandValue(node, command), newValue)) {
    return;
  }

  // "If node is not an allowed child of "span":"
  if (!isAllowedChild(node, "span")) {
    // "Let children be all children of node, omitting any that are
    // Elements whose specified command value for command is neither null
    // nor equivalent to new value."
    var children = [];
    for (var i = 0; i < node.childNodes.length; i++) {
      if (node.childNodes[i].nodeType == Node.ELEMENT_NODE) {
        var specifiedValue = getSpecifiedCommandValue(node.childNodes[i], command);

        if (specifiedValue !== null
        && !areEquivalentValues(command, newValue, specifiedValue)) {
          continue;
        }
      }
      children.push(node.childNodes[i]);
    }

    // "Force the value of each Node in children, with command and new
    // value as in this invocation of the algorithm."
    for (var i = 0; i < children.length; i++) {
      forceValue(children[i], command, newValue);
    }

    // "Abort this algorithm."
    return;
  }

  // "If the effective command value of command is loosely equivalent to new
  // value on node, abort this algorithm."
  if (areLooselyEquivalentValues(command, getEffectiveCommandValue(node, command), newValue)) {
    return;
  }

  // "Let new parent be null."
  var newParent = null;

  // "If the CSS styling flag is false:"
  if (!cssStylingFlag) {
    // "If command is "bold" and new value is "bold", let new parent be the
    // result of calling createElement("b") on the ownerDocument of node."
    if (command == "bold" && (newValue == "bold" || newValue == "700")) {
      newParent = node.ownerDocument.createElement("b");
    }

    // "If command is "italic" and new value is "italic", let new parent be
    // the result of calling createElement("i") on the ownerDocument of
    // node."
    if (command == "italic" && newValue == "italic") {
      newParent = node.ownerDocument.createElement("i");
    }

    // "If command is "strikethrough" and new value is "line-through", let
    // new parent be the result of calling createElement("s") on the
    // ownerDocument of node."
    if (command == "strikethrough" && newValue == "line-through") {
      newParent = node.ownerDocument.createElement("s");
    }

    // "If command is "underline" and new value is "underline", let new
    // parent be the result of calling createElement("u") on the
    // ownerDocument of node."
    if (command == "underline" && newValue == "underline") {
      newParent = node.ownerDocument.createElement("u");
    }

    // "If command is "foreColor", and new value is fully opaque with red,
    // green, and blue components in the range 0 to 255:"
    if (command == "forecolor" && parseSimpleColor(newValue)) {
      // "Let new parent be the result of calling createElement("font")
      // on the ownerDocument of node."
      newParent = node.ownerDocument.createElement("font");

      // "Set the color attribute of new parent to the result of applying
      // the rules for serializing simple color values to new value
      // (interpreted as a simple color)."
      newParent.setAttribute("color", parseSimpleColor(newValue));
    }

    // "If command is "fontName", let new parent be the result of calling
    // createElement("font") on the ownerDocument of node, then set the
    // face attribute of new parent to new value."
    if (command == "fontname") {
      newParent = node.ownerDocument.createElement("font");
      newParent.face = newValue;
    }
  }

  // "If command is "createLink" or "unlink":"
  if (command == "createlink" || command == "unlink") {
    // "Let new parent be the result of calling createElement("a") on the
    // ownerDocument of node."
    newParent = node.ownerDocument.createElement("a");

    // "Set the href attribute of new parent to new value."
    newParent.setAttribute("href", newValue);

    // "Let ancestor be node's parent."
    var ancestor = node.parentNode;

    // "While ancestor is not null:"
    while (ancestor) {
      // "If ancestor is an a, set the tag name of ancestor to "span",
      // and let ancestor be the result."
      if (isHtmlElement(ancestor, "A")) {
        ancestor = setTagName(ancestor, "span");
      }

      // "Set ancestor to its parent."
      ancestor = ancestor.parentNode;
    }
  }

  // "If command is "fontSize"; and new value is one of "x-small", "small",
  // "medium", "large", "x-large", "xx-large", or "xxx-large"; and either the
  // CSS styling flag is false, or new value is "xxx-large": let new parent
  // be the result of calling createElement("font") on the ownerDocument of
  // node, then set the size attribute of new parent to the number from the
  // following table based on new value: [table omitted]"
  if (command == "fontsize"
  && ["x-small", "small", "medium", "large", "x-large", "xx-large", "xxx-large"].indexOf(newValue) != -1
  && (!cssStylingFlag || newValue == "xxx-large")) {
    newParent = node.ownerDocument.createElement("font");
    newParent.size = cssSizeToLegacy(newValue);
  }

  // "If command is "subscript" or "superscript" and new value is
  // "subscript", let new parent be the result of calling
  // createElement("sub") on the ownerDocument of node."
  if ((command == "subscript" || command == "superscript")
  && newValue == "subscript") {
    newParent = node.ownerDocument.createElement("sub");
  }

  // "If command is "subscript" or "superscript" and new value is
  // "superscript", let new parent be the result of calling
  // createElement("sup") on the ownerDocument of node."
  if ((command == "subscript" || command == "superscript")
  && newValue == "superscript") {
    newParent = node.ownerDocument.createElement("sup");
  }

  // "If new parent is null, let new parent be the result of calling
  // createElement("span") on the ownerDocument of node."
  if (!newParent) {
    newParent = node.ownerDocument.createElement("span");
  }

  // "Insert new parent in node's parent before node."
  node.parentNode.insertBefore(newParent, node);

  // "If the effective command value of command for new parent is not loosely
  // equivalent to new value, and the relevant CSS property for command is
  // not null, set that CSS property of new parent to new value (if the new
  // value would be valid)."
  var property = commands[command].relevantCssProperty;
  if (property !== null
  && !areLooselyEquivalentValues(command, getEffectiveCommandValue(newParent, command), newValue)) {
    newParent.style[property] = newValue;
  }

  // "If command is "strikethrough", and new value is "line-through", and the
  // effective command value of "strikethrough" for new parent is not
  // "line-through", set the "text-decoration" property of new parent to
  // "line-through"."
  if (command == "strikethrough"
  && newValue == "line-through"
  && getEffectiveCommandValue(newParent, "strikethrough") != "line-through") {
    newParent.style.textDecoration = "line-through";
  }

  // "If command is "underline", and new value is "underline", and the
  // effective command value of "underline" for new parent is not
  // "underline", set the "text-decoration" property of new parent to
  // "underline"."
  if (command == "underline"
  && newValue == "underline"
  && getEffectiveCommandValue(newParent, "underline") != "underline") {
    newParent.style.textDecoration = "underline";
  }

  // "Append node to new parent as its last child, preserving ranges."
  movePreservingRanges(node, newParent, newParent.childNodes.length);

  // "If node is an Element and the effective command value of command for
  // node is not loosely equivalent to new value:"
  if (node.nodeType == Node.ELEMENT_NODE
  && !areEquivalentValues(command, getEffectiveCommandValue(node, command), newValue)) {
    // "Insert node into the parent of new parent before new parent,
    // preserving ranges."
    movePreservingRanges(node, newParent.parentNode, getNodeIndex(newParent));

    // "Remove new parent from its parent."
    newParent.parentNode.removeChild(newParent);

    // "Let children be all children of node, omitting any that are
    // Elements whose specified command value for command is neither null
    // nor equivalent to new value."
    var children = [];
    for (var i = 0; i < node.childNodes.length; i++) {
      if (node.childNodes[i].nodeType == Node.ELEMENT_NODE) {
        var specifiedValue = getSpecifiedCommandValue(node.childNodes[i], command);

        if (specifiedValue !== null
        && !areEquivalentValues(command, newValue, specifiedValue)) {
          continue;
        }
      }
      children.push(node.childNodes[i]);
    }

    // "Force the value of each Node in children, with command and new
    // value as in this invocation of the algorithm."
    for (var i = 0; i < children.length; i++) {
      forceValue(children[i], command, newValue);
    }
  }
}


//@}
///// Setting the selection's value /////
//@{

function setSelectionValue(command, newValue) {
  // "If there is no formattable node effectively contained in the active
  // range:"
  if (!getAllEffectivelyContainedNodes(getActiveRange())
  .some(isFormattableNode)) {
    // "If command has inline command activated values, set the state
    // override to true if new value is among them and false if it's not."
    if ("inlineCommandActivatedValues" in commands[command]) {
      setStateOverride(command, commands[command].inlineCommandActivatedValues
        .indexOf(newValue) != -1);
    }

    // "If command is "subscript", unset the state override for
    // "superscript"."
    if (command == "subscript") {
      unsetStateOverride("superscript");
    }

    // "If command is "superscript", unset the state override for
    // "subscript"."
    if (command == "superscript") {
      unsetStateOverride("subscript");
    }

    // "If new value is null, unset the value override (if any)."
    if (newValue === null) {
      unsetValueOverride(command);

    // "Otherwise, if command is "createLink" or it has a value specified,
    // set the value override to new value."
    } else if (command == "createlink" || "value" in commands[command]) {
      setValueOverride(command, newValue);
    }

    // "Abort these steps."
    return;
  }

  // "If the active range's start node is an editable Text node, and its
  // start offset is neither zero nor its start node's length, call
  // splitText() on the active range's start node, with argument equal to the
  // active range's start offset. Then set the active range's start node to
  // the result, and its start offset to zero."
  if (isEditable(getActiveRange().startContainer)
  && getActiveRange().startContainer.nodeType == Node.TEXT_NODE
  && getActiveRange().startOffset != 0
  && getActiveRange().startOffset != getNodeLength(getActiveRange().startContainer)) {
    // Account for browsers not following range mutation rules
    var newActiveRange = document.createRange();
    var newNode;
    if (getActiveRange().startContainer == getActiveRange().endContainer) {
      var newEndOffset = getActiveRange().endOffset - getActiveRange().startOffset;
      newNode = getActiveRange().startContainer.splitText(getActiveRange().startOffset);
      newActiveRange.setEnd(newNode, newEndOffset);
      getActiveRange().setEnd(newNode, newEndOffset);
    } else {
      newNode = getActiveRange().startContainer.splitText(getActiveRange().startOffset);
    }
    newActiveRange.setStart(newNode, 0);
    getSelection().removeAllRanges();
    getSelection().addRange(newActiveRange);

    getActiveRange().setStart(newNode, 0);
  }

  // "If the active range's end node is an editable Text node, and its end
  // offset is neither zero nor its end node's length, call splitText() on
  // the active range's end node, with argument equal to the active range's
  // end offset."
  if (isEditable(getActiveRange().endContainer)
  && getActiveRange().endContainer.nodeType == Node.TEXT_NODE
  && getActiveRange().endOffset != 0
  && getActiveRange().endOffset != getNodeLength(getActiveRange().endContainer)) {
    // IE seems to mutate the range incorrectly here, so we need correction
    // here as well.  The active range will be temporarily in orphaned
    // nodes, so calling getActiveRange() after splitText() but before
    // fixing the range will throw an exception.
    var activeRange = getActiveRange();
    var newStart = [activeRange.startContainer, activeRange.startOffset];
    var newEnd = [activeRange.endContainer, activeRange.endOffset];
    activeRange.endContainer.splitText(activeRange.endOffset);
    activeRange.setStart(newStart[0], newStart[1]);
    activeRange.setEnd(newEnd[0], newEnd[1]);

    getSelection().removeAllRanges();
    getSelection().addRange(activeRange);
  }

  // "Let element list be all editable Elements effectively contained in the
  // active range.
  //
  // "For each element in element list, clear the value of element."
  getAllEffectivelyContainedNodes(getActiveRange(), function(node) {
    return isEditable(node) && node.nodeType == Node.ELEMENT_NODE;
  }).forEach(function(element) {
    clearValue(element, command);
  });

  // "Let node list be all editable nodes effectively contained in the active
  // range.
  //
  // "For each node in node list:"
  getAllEffectivelyContainedNodes(getActiveRange(), isEditable).forEach(function(node) {
    // "Push down values on node."
    pushDownValues(node, command, newValue);

    // "If node is an allowed child of span, force the value of node."
    if (isAllowedChild(node, "span")) {
      forceValue(node, command, newValue);
    }
  });
}


//@}
///// The backColor command /////
//@{
commands.backcolor = {
  // Copy-pasted, same as hiliteColor
  action: function(value) {
    // Action is further copy-pasted, same as foreColor

    // "If value is not a valid CSS color, prepend "#" to it."
    //
    // "If value is still not a valid CSS color, or if it is currentColor,
    // return false."
    //
    // Cheap hack for testing, no attempt to be comprehensive.
    if (/^([0-9a-fA-F]{3}){1,2}$/.test(value)) {
      value = "#" + value;
    }
    if (!/^(rgba?|hsla?)\(.*\)$/.test(value)
    && !parseSimpleColor(value)
    && value.toLowerCase() != "transparent") {
      return false;
    }

    // "Set the selection's value to value."
    setSelectionValue("backcolor", value);

    // "Return true."
    return true;
  }, standardInlineValueCommand: true, relevantCssProperty: "backgroundColor",
  equivalentValues: function(val1, val2) {
    // "Either both strings are valid CSS colors and have the same red,
    // green, blue, and alpha components, or neither string is a valid CSS
    // color."
    return normalizeColor(val1) === normalizeColor(val2);
  },
};

//@}
///// The bold command /////
//@{
commands.bold = {
  action: function() {
    // "If queryCommandState("bold") returns true, set the selection's
    // value to "normal". Otherwise set the selection's value to "bold".
    // Either way, return true."
    if (myQueryCommandState("bold")) {
      setSelectionValue("bold", "normal");
    } else {
      setSelectionValue("bold", "bold");
    }
    return true;
  }, inlineCommandActivatedValues: ["bold", "600", "700", "800", "900"],
  relevantCssProperty: "fontWeight",
  equivalentValues: function(val1, val2) {
    // "Either the two strings are equal, or one is "bold" and the other is
    // "700", or one is "normal" and the other is "400"."
    return val1 == val2
      || (val1 == "bold" && val2 == "700")
      || (val1 == "700" && val2 == "bold")
      || (val1 == "normal" && val2 == "400")
      || (val1 == "400" && val2 == "normal");
  },
};

//@}
///// The createLink command /////
//@{
commands.createlink = {
  action: function(value) {
    // "If value is the empty string, return false."
    if (value === "") {
      return false;
    }

    // "For each editable a element that has an href attribute and is an
    // ancestor of some node effectively contained in the active range, set
    // that a element's href attribute to value."
    //
    // TODO: We don't actually do this in tree order, not that it matters
    // unless you're spying with mutation events.
    getAllEffectivelyContainedNodes(getActiveRange()).forEach(function(node) {
      getAncestors(node).forEach(function(ancestor) {
        if (isEditable(ancestor)
        && isHtmlElement(ancestor, "a")
        && ancestor.hasAttribute("href")) {
          ancestor.setAttribute("href", value);
        }
      });
    });

    // "Set the selection's value to value."
    setSelectionValue("createlink", value);

    // "Return true."
    return true;
  }
};

//@}
///// The fontName command /////
//@{
commands.fontname = {
  action: function(value) {
    // "Set the selection's value to value, then return true."
    setSelectionValue("fontname", value);
    return true;
  }, standardInlineValueCommand: true, relevantCssProperty: "fontFamily"
};

//@}
///// The fontSize command /////
//@{

// Helper function for fontSize's action plus queryOutputHelper.  It's just the
// middle of fontSize's action, ripped out into its own function.  Returns null
// if the size is invalid.
function normalizeFontSize(value) {
  // "Strip leading and trailing whitespace from value."
  //
  // Cheap hack, not following the actual algorithm.
  value = value.trim();

  // "If value is not a valid floating point number, and would not be a valid
  // floating point number if a single leading "+" character were stripped,
  // return false."
  if (!/^[-+]?[0-9]+(\.[0-9]+)?([eE][-+]?[0-9]+)?$/.test(value)) {
    return null;
  }

  var mode;

  // "If the first character of value is "+", delete the character and let
  // mode be "relative-plus"."
  if (value[0] == "+") {
    value = value.slice(1);
    mode = "relative-plus";
  // "Otherwise, if the first character of value is "-", delete the character
  // and let mode be "relative-minus"."
  } else if (value[0] == "-") {
    value = value.slice(1);
    mode = "relative-minus";
  // "Otherwise, let mode be "absolute"."
  } else {
    mode = "absolute";
  }

  // "Apply the rules for parsing non-negative integers to value, and let
  // number be the result."
  //
  // Another cheap hack.
  var num = parseInt(value);

  // "If mode is "relative-plus", add three to number."
  if (mode == "relative-plus") {
    num += 3;
  }

  // "If mode is "relative-minus", negate number, then add three to it."
  if (mode == "relative-minus") {
    num = 3 - num;
  }

  // "If number is less than one, let number equal 1."
  if (num < 1) {
    num = 1;
  }

  // "If number is greater than seven, let number equal 7."
  if (num > 7) {
    num = 7;
  }

  // "Set value to the string here corresponding to number:" [table omitted]
  value = {
    1: "x-small",
    2: "small",
    3: "medium",
    4: "large",
    5: "x-large",
    6: "xx-large",
    7: "xxx-large"
  }[num];

  return value;
}

commands.fontsize = {
  action: function(value) {
    value = normalizeFontSize(value);
    if (value === null) {
      return false;
    }

    // "Set the selection's value to value."
    setSelectionValue("fontsize", value);

    // "Return true."
    return true;
  }, indeterm: function() {
    // "True if among formattable nodes that are effectively contained in
    // the active range, there are two that have distinct effective command
    // values.  Otherwise false."
    return getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode)
    .map(function(node) {
      return getEffectiveCommandValue(node, "fontsize");
    }).filter(function(value, i, arr) {
      return arr.slice(0, i).indexOf(value) == -1;
    }).length >= 2;
  }, value: function() {
    // "If the active range is null, return the empty string."
    if (!getActiveRange()) {
      return "";
    }

    // "Let pixel size be the effective command value of the first
    // formattable node that is effectively contained in the active range,
    // or if there is no such node, the effective command value of the
    // active range's start node, in either case interpreted as a number of
    // pixels."
    var node = getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode)[0];
    if (node === undefined) {
      node = getActiveRange().startContainer;
    }
    var pixelSize = getEffectiveCommandValue(node, "fontsize");

    // "Return the legacy font size for pixel size."
    return getLegacyFontSize(pixelSize);
  }, relevantCssProperty: "fontSize"
};

function getLegacyFontSize(size) {
  if (getLegacyFontSize.resultCache === undefined) {
    getLegacyFontSize.resultCache = {};
  }

  if (getLegacyFontSize.resultCache[size] !== undefined) {
    return getLegacyFontSize.resultCache[size];
  }

  // For convenience in other places in my code, I handle all sizes, not just
  // pixel sizes as the spec says.  This means pixel sizes have to be passed
  // in suffixed with "px", not as plain numbers.
  if (normalizeFontSize(size) !== null) {
    return getLegacyFontSize.resultCache[size] = cssSizeToLegacy(normalizeFontSize(size));
  }

  if (["x-small", "x-small", "small", "medium", "large", "x-large", "xx-large", "xxx-large"].indexOf(size) == -1
  && !/^[0-9]+(\.[0-9]+)?(cm|mm|in|pt|pc|px)$/.test(size)) {
    // There is no sensible legacy size for things like "2em".
    return getLegacyFontSize.resultCache[size] = null;
  }

  var font = document.createElement("font");
  document.body.appendChild(font);
  if (size == "xxx-large") {
    font.size = 7;
  } else {
    font.style.fontSize = size;
  }
  var pixelSize = parseInt(getComputedStyle(font).fontSize);
  document.body.removeChild(font);

  // "Let returned size be 1."
  var returnedSize = 1;

  // "While returned size is less than 7:"
  while (returnedSize < 7) {
    // "Let lower bound be the resolved value of "font-size" in pixels
    // of a font element whose size attribute is set to returned size."
    var font = document.createElement("font");
    font.size = returnedSize;
    document.body.appendChild(font);
    var lowerBound = parseInt(getComputedStyle(font).fontSize);

    // "Let upper bound be the resolved value of "font-size" in pixels
    // of a font element whose size attribute is set to one plus
    // returned size."
    font.size = 1 + returnedSize;
    var upperBound = parseInt(getComputedStyle(font).fontSize);
    document.body.removeChild(font);

    // "Let average be the average of upper bound and lower bound."
    var average = (upperBound + lowerBound)/2;

    // "If pixel size is less than average, return the one-element
    // string consisting of the digit returned size."
    if (pixelSize < average) {
      return getLegacyFontSize.resultCache[size] = String(returnedSize);
    }

    // "Add one to returned size."
    returnedSize++;
  }

  // "Return "7"."
  return getLegacyFontSize.resultCache[size] = "7";
}

//@}
///// The foreColor command /////
//@{
commands.forecolor = {
  action: function(value) {
    // Copy-pasted, same as backColor and hiliteColor

    // "If value is not a valid CSS color, prepend "#" to it."
    //
    // "If value is still not a valid CSS color, or if it is currentColor,
    // return false."
    //
    // Cheap hack for testing, no attempt to be comprehensive.
    if (/^([0-9a-fA-F]{3}){1,2}$/.test(value)) {
      value = "#" + value;
    }
    if (!/^(rgba?|hsla?)\(.*\)$/.test(value)
    && !parseSimpleColor(value)
    && value.toLowerCase() != "transparent") {
      return false;
    }

    // "Set the selection's value to value."
    setSelectionValue("forecolor", value);

    // "Return true."
    return true;
  }, standardInlineValueCommand: true, relevantCssProperty: "color",
  equivalentValues: function(val1, val2) {
    // "Either both strings are valid CSS colors and have the same red,
    // green, blue, and alpha components, or neither string is a valid CSS
    // color."
    return normalizeColor(val1) === normalizeColor(val2);
  },
};

//@}
///// The hiliteColor command /////
//@{
commands.hilitecolor = {
  // Copy-pasted, same as backColor
  action: function(value) {
    // Action is further copy-pasted, same as foreColor

    // "If value is not a valid CSS color, prepend "#" to it."
    //
    // "If value is still not a valid CSS color, or if it is currentColor,
    // return false."
    //
    // Cheap hack for testing, no attempt to be comprehensive.
    if (/^([0-9a-fA-F]{3}){1,2}$/.test(value)) {
      value = "#" + value;
    }
    if (!/^(rgba?|hsla?)\(.*\)$/.test(value)
    && !parseSimpleColor(value)
    && value.toLowerCase() != "transparent") {
      return false;
    }

    // "Set the selection's value to value."
    setSelectionValue("hilitecolor", value);

    // "Return true."
    return true;
  }, indeterm: function() {
    // "True if among editable Text nodes that are effectively contained in
    // the active range, there are two that have distinct effective command
    // values.  Otherwise false."
    return getAllEffectivelyContainedNodes(getActiveRange(), function(node) {
      return isEditable(node) && node.nodeType == Node.TEXT_NODE;
    }).map(function(node) {
      return getEffectiveCommandValue(node, "hilitecolor");
    }).filter(function(value, i, arr) {
      return arr.slice(0, i).indexOf(value) == -1;
    }).length >= 2;
  }, standardInlineValueCommand: true, relevantCssProperty: "backgroundColor",
  equivalentValues: function(val1, val2) {
    // "Either both strings are valid CSS colors and have the same red,
    // green, blue, and alpha components, or neither string is a valid CSS
    // color."
    return normalizeColor(val1) === normalizeColor(val2);
  },
};

//@}
///// The italic command /////
//@{
commands.italic = {
  action: function() {
    // "If queryCommandState("italic") returns true, set the selection's
    // value to "normal". Otherwise set the selection's value to "italic".
    // Either way, return true."
    if (myQueryCommandState("italic")) {
      setSelectionValue("italic", "normal");
    } else {
      setSelectionValue("italic", "italic");
    }
    return true;
  }, inlineCommandActivatedValues: ["italic", "oblique"],
  relevantCssProperty: "fontStyle"
};

//@}
///// The removeFormat command /////
//@{
commands.removeformat = {
  action: function() {
    // "A removeFormat candidate is an editable HTML element with local
    // name "abbr", "acronym", "b", "bdi", "bdo", "big", "blink", "cite",
    // "code", "dfn", "em", "font", "i", "ins", "kbd", "mark", "nobr", "q",
    // "s", "samp", "small", "span", "strike", "strong", "sub", "sup",
    // "tt", "u", or "var"."
    function isRemoveFormatCandidate(node) {
      return isEditable(node)
        && isHtmlElement(node, ["abbr", "acronym", "b", "bdi", "bdo",
        "big", "blink", "cite", "code", "dfn", "em", "font", "i",
        "ins", "kbd", "mark", "nobr", "q", "s", "samp", "small",
        "span", "strike", "strong", "sub", "sup", "tt", "u", "var"]);
    }

    // "Let elements to remove be a list of every removeFormat candidate
    // effectively contained in the active range."
    var elementsToRemove = getAllEffectivelyContainedNodes(getActiveRange(), isRemoveFormatCandidate);

    // "For each element in elements to remove:"
    elementsToRemove.forEach(function(element) {
      // "While element has children, insert the first child of element
      // into the parent of element immediately before element,
      // preserving ranges."
      while (element.hasChildNodes()) {
        movePreservingRanges(element.firstChild, element.parentNode, getNodeIndex(element));
      }

      // "Remove element from its parent."
      element.parentNode.removeChild(element);
    });

    // "If the active range's start node is an editable Text node, and its
    // start offset is neither zero nor its start node's length, call
    // splitText() on the active range's start node, with argument equal to
    // the active range's start offset. Then set the active range's start
    // node to the result, and its start offset to zero."
    if (isEditable(getActiveRange().startContainer)
    && getActiveRange().startContainer.nodeType == Node.TEXT_NODE
    && getActiveRange().startOffset != 0
    && getActiveRange().startOffset != getNodeLength(getActiveRange().startContainer)) {
      // Account for browsers not following range mutation rules
      if (getActiveRange().startContainer == getActiveRange().endContainer) {
        var newEnd = getActiveRange().endOffset - getActiveRange().startOffset;
        var newNode = getActiveRange().startContainer.splitText(getActiveRange().startOffset);
        getActiveRange().setStart(newNode, 0);
        getActiveRange().setEnd(newNode, newEnd);
      } else {
        getActiveRange().setStart(getActiveRange().startContainer.splitText(getActiveRange().startOffset), 0);
      }
    }

    // "If the active range's end node is an editable Text node, and its
    // end offset is neither zero nor its end node's length, call
    // splitText() on the active range's end node, with argument equal to
    // the active range's end offset."
    if (isEditable(getActiveRange().endContainer)
    && getActiveRange().endContainer.nodeType == Node.TEXT_NODE
    && getActiveRange().endOffset != 0
    && getActiveRange().endOffset != getNodeLength(getActiveRange().endContainer)) {
      // IE seems to mutate the range incorrectly here, so we need
      // correction here as well.  Have to be careful to set the range to
      // something not including the text node so that getActiveRange()
      // doesn't throw an exception due to a temporarily detached
      // endpoint.
      var newStart = [getActiveRange().startContainer, getActiveRange().startOffset];
      var newEnd = [getActiveRange().endContainer, getActiveRange().endOffset];
      getActiveRange().setEnd(document.documentElement, 0);
      newEnd[0].splitText(newEnd[1]);
      getActiveRange().setStart(newStart[0], newStart[1]);
      getActiveRange().setEnd(newEnd[0], newEnd[1]);
    }

    // "Let node list consist of all editable nodes effectively contained
    // in the active range."
    //
    // "For each node in node list, while node's parent is a removeFormat
    // candidate in the same editing host as node, split the parent of the
    // one-node list consisting of node."
    getAllEffectivelyContainedNodes(getActiveRange(), isEditable).forEach(function(node) {
      while (isRemoveFormatCandidate(node.parentNode)
      && inSameEditingHost(node.parentNode, node)) {
        splitParent([node]);
      }
    });

    // "For each of the entries in the following list, in the given order,
    // set the selection's value to null, with command as given."
    [
      "subscript",
      "bold",
      "fontname",
      "fontsize",
      "forecolor",
      "hilitecolor",
      "italic",
      "strikethrough",
      "underline",
    ].forEach(function(command) {
      setSelectionValue(command, null);
    });

    // "Return true."
    return true;
  }
};

//@}
///// The strikethrough command /////
//@{
commands.strikethrough = {
  action: function() {
    // "If queryCommandState("strikethrough") returns true, set the
    // selection's value to null. Otherwise set the selection's value to
    // "line-through".  Either way, return true."
    if (myQueryCommandState("strikethrough")) {
      setSelectionValue("strikethrough", null);
    } else {
      setSelectionValue("strikethrough", "line-through");
    }
    return true;
  }, inlineCommandActivatedValues: ["line-through"]
};

//@}
///// The subscript command /////
//@{
commands.subscript = {
  action: function() {
    // "Call queryCommandState("subscript"), and let state be the result."
    var state = myQueryCommandState("subscript");

    // "Set the selection's value to null."
    setSelectionValue("subscript", null);

    // "If state is false, set the selection's value to "subscript"."
    if (!state) {
      setSelectionValue("subscript", "subscript");
    }

    // "Return true."
    return true;
  }, indeterm: function() {
    // "True if either among formattable nodes that are effectively
    // contained in the active range, there is at least one with effective
    // command value "subscript" and at least one with some other effective
    // command value; or if there is some formattable node effectively
    // contained in the active range with effective command value "mixed".
    // Otherwise false."
    var nodes = getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode);
    return (nodes.some(function(node) { return getEffectiveCommandValue(node, "subscript") == "subscript" })
      && nodes.some(function(node) { return getEffectiveCommandValue(node, "subscript") != "subscript" }))
      || nodes.some(function(node) { return getEffectiveCommandValue(node, "subscript") == "mixed" });
  }, inlineCommandActivatedValues: ["subscript"],
};

//@}
///// The superscript command /////
//@{
commands.superscript = {
  action: function() {
    // "Call queryCommandState("superscript"), and let state be the
    // result."
    var state = myQueryCommandState("superscript");

    // "Set the selection's value to null."
    setSelectionValue("superscript", null);

    // "If state is false, set the selection's value to "superscript"."
    if (!state) {
      setSelectionValue("superscript", "superscript");
    }

    // "Return true."
    return true;
  }, indeterm: function() {
    // "True if either among formattable nodes that are effectively
    // contained in the active range, there is at least one with effective
    // command value "superscript" and at least one with some other
    // effective command value; or if there is some formattable node
    // effectively contained in the active range with effective command
    // value "mixed".  Otherwise false."
    var nodes = getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode);
    return (nodes.some(function(node) { return getEffectiveCommandValue(node, "superscript") == "superscript" })
      && nodes.some(function(node) { return getEffectiveCommandValue(node, "superscript") != "superscript" }))
      || nodes.some(function(node) { return getEffectiveCommandValue(node, "superscript") == "mixed" });
  }, inlineCommandActivatedValues: ["superscript"],
};

//@}
///// The underline command /////
//@{
commands.underline = {
  action: function() {
    // "If queryCommandState("underline") returns true, set the selection's
    // value to null. Otherwise set the selection's value to "underline".
    // Either way, return true."
    if (myQueryCommandState("underline")) {
      setSelectionValue("underline", null);
    } else {
      setSelectionValue("underline", "underline");
    }
    return true;
  }, inlineCommandActivatedValues: ["underline"]
};

//@}
///// The unlink command /////
//@{
commands.unlink = {
  action: function() {
    // "Let hyperlinks be a list of every a element that has an href
    // attribute and is contained in the active range or is an ancestor of
    // one of its boundary points."
    //
    // As usual, take care to ensure it's tree order.  The correctness of
    // the following is left as an exercise for the reader.
    var range = getActiveRange();
    var hyperlinks = [];
    for (
      var node = range.startContainer;
      node;
      node = node.parentNode
    ) {
      if (isHtmlElement(node, "A")
      && node.hasAttribute("href")) {
        hyperlinks.unshift(node);
      }
    }
    for (
      var node = range.startContainer;
      node != nextNodeDescendants(range.endContainer);
      node = nextNode(node)
    ) {
      if (isHtmlElement(node, "A")
      && node.hasAttribute("href")
      && (isContained(node, range)
      || isAncestor(node, range.endContainer)
      || node == range.endContainer)) {
        hyperlinks.push(node);
      }
    }

    // "Clear the value of each member of hyperlinks."
    for (var i = 0; i < hyperlinks.length; i++) {
      clearValue(hyperlinks[i], "unlink");
    }

    // "Return true."
    return true;
  }
};

//@}

/////////////////////////////////////
///// Block formatting commands /////
/////////////////////////////////////

///// Block formatting command definitions /////
//@{

// "An indentation element is either a blockquote, or a div that has a style
// attribute that sets "margin" or some subproperty of it."
function isIndentationElement(node) {
  if (!isHtmlElement(node)) {
    return false;
  }

  if (node.tagName == "BLOCKQUOTE") {
    return true;
  }

  if (node.tagName != "DIV") {
    return false;
  }

  for (var i = 0; i < node.style.length; i++) {
    // Approximate check
    if (/^(-[a-z]+-)?margin/.test(node.style[i])) {
      return true;
    }
  }

  return false;
}

// "A simple indentation element is an indentation element that has no
// attributes except possibly
//
//   * "a style attribute that sets no properties other than "margin",
//     "border", "padding", or subproperties of those; and/or
//   * "a dir attribute."
function isSimpleIndentationElement(node) {
  if (!isIndentationElement(node)) {
    return false;
  }

  for (var i = 0; i < node.attributes.length; i++) {
    if (!isHtmlNamespace(node.attributes[i].namespaceURI)
    || ["style", "dir"].indexOf(node.attributes[i].name) == -1) {
      return false;
    }
  }

  for (var i = 0; i < node.style.length; i++) {
    // This is approximate, but it works well enough for my purposes.
    if (!/^(-[a-z]+-)?(margin|border|padding)/.test(node.style[i])) {
      return false;
    }
  }

  return true;
}

// "A non-list single-line container is an HTML element with local name
// "address", "div", "h1", "h2", "h3", "h4", "h5", "h6", "listing", "p", "pre",
// or "xmp"."
function isNonListSingleLineContainer(node) {
  return isHtmlElement(node, ["address", "div", "h1", "h2", "h3", "h4", "h5",
    "h6", "listing", "p", "pre", "xmp"]);
}

// "A single-line container is either a non-list single-line container, or an
// HTML element with local name "li", "dt", or "dd"."
function isSingleLineContainer(node) {
  return isNonListSingleLineContainer(node)
    || isHtmlElement(node, ["li", "dt", "dd"]);
}

function getBlockNodeOf(node) {
  // "While node is an inline node, set node to its parent."
  while (isInlineNode(node)) {
    node = node.parentNode;
  }

  // "Return node."
  return node;
}

//@}
///// Assorted block formatting command algorithms /////
//@{

function fixDisallowedAncestors(node) {
  // "If node is not editable, abort these steps."
  if (!isEditable(node)) {
    return;
  }

  // "If node is not an allowed child of any of its ancestors in the same
  // editing host:"
  if (getAncestors(node).every(function(ancestor) {
    return !inSameEditingHost(node, ancestor)
      || !isAllowedChild(node, ancestor)
  })) {
    // "If node is a dd or dt, wrap the one-node list consisting of node,
    // with sibling criteria returning true for any dl with no attributes
    // and false otherwise, and new parent instructions returning the
    // result of calling createElement("dl") on the context object. Then
    // abort these steps."
    if (isHtmlElement(node, ["dd", "dt"])) {
      wrap([node],
        function(sibling) { return isHtmlElement(sibling, "dl") && !sibling.attributes.length },
        function() { return document.createElement("dl") });
      return;
    }

    // "If "p" is not an allowed child of the editing host of node, abort
    // these steps."
    if (!isAllowedChild("p", getEditingHostOf(node))) {
      return;
    }

    // "If node is not a prohibited paragraph child, abort these steps."
    if (!isProhibitedParagraphChild(node)) {
      return;
    }

    // "Set the tag name of node to the default single-line container name,
    // and let node be the result."
    node = setTagName(node, defaultSingleLineContainerName);

    // "Fix disallowed ancestors of node."
    fixDisallowedAncestors(node);

    // "Let children be node's children."
    var children = [].slice.call(node.childNodes);

    // "For each child in children, if child is a prohibited paragraph
    // child:"
    children.filter(isProhibitedParagraphChild)
    .forEach(function(child) {
      // "Record the values of the one-node list consisting of child, and
      // let values be the result."
      var values = recordValues([child]);

      // "Split the parent of the one-node list consisting of child."
      splitParent([child]);

      // "Restore the values from values."
      restoreValues(values);
    });

    // "Abort these steps."
    return;
  }

  // "Record the values of the one-node list consisting of node, and let
  // values be the result."
  var values = recordValues([node]);

  // "While node is not an allowed child of its parent, split the parent of
  // the one-node list consisting of node."
  while (!isAllowedChild(node, node.parentNode)) {
    splitParent([node]);
  }

  // "Restore the values from values."
  restoreValues(values);
}

function normalizeSublists(item) {
  // "If item is not an li or it is not editable or its parent is not
  // editable, abort these steps."
  if (!isHtmlElement(item, "LI")
  || !isEditable(item)
  || !isEditable(item.parentNode)) {
    return;
  }

  // "Let new item be null."
  var newItem = null;

  // "While item has an ol or ul child:"
  while ([].some.call(item.childNodes, function (node) { return isHtmlElement(node, ["OL", "UL"]) })) {
    // "Let child be the last child of item."
    var child = item.lastChild;

    // "If child is an ol or ul, or new item is null and child is a Text
    // node whose data consists of zero of more space characters:"
    if (isHtmlElement(child, ["OL", "UL"])
    || (!newItem && child.nodeType == Node.TEXT_NODE && /^[ \t\n\f\r]*$/.test(child.data))) {
      // "Set new item to null."
      newItem = null;

      // "Insert child into the parent of item immediately following
      // item, preserving ranges."
      movePreservingRanges(child, item.parentNode, 1 + getNodeIndex(item));

    // "Otherwise:"
    } else {
      // "If new item is null, let new item be the result of calling
      // createElement("li") on the ownerDocument of item, then insert
      // new item into the parent of item immediately after item."
      if (!newItem) {
        newItem = item.ownerDocument.createElement("li");
        item.parentNode.insertBefore(newItem, item.nextSibling);
      }

      // "Insert child into new item as its first child, preserving
      // ranges."
      movePreservingRanges(child, newItem, 0);
    }
  }
}

function getSelectionListState() {
  // "If the active range is null, return "none"."
  if (!getActiveRange()) {
    return "none";
  }

  // "Block-extend the active range, and let new range be the result."
  var newRange = blockExtend(getActiveRange());

  // "Let node list be a list of nodes, initially empty."
  //
  // "For each node contained in new range, append node to node list if the
  // last member of node list (if any) is not an ancestor of node; node is
  // editable; node is not an indentation element; and node is either an ol
  // or ul, or the child of an ol or ul, or an allowed child of "li"."
  var nodeList = getContainedNodes(newRange, function(node) {
    return isEditable(node)
      && !isIndentationElement(node)
      && (isHtmlElement(node, ["ol", "ul"])
      || isHtmlElement(node.parentNode, ["ol", "ul"])
      || isAllowedChild(node, "li"));
  });

  // "If node list is empty, return "none"."
  if (!nodeList.length) {
    return "none";
  }

  // "If every member of node list is either an ol or the child of an ol or
  // the child of an li child of an ol, and none is a ul or an ancestor of a
  // ul, return "ol"."
  if (nodeList.every(function(node) {
    return isHtmlElement(node, "ol")
      || isHtmlElement(node.parentNode, "ol")
      || (isHtmlElement(node.parentNode, "li") && isHtmlElement(node.parentNode.parentNode, "ol"));
  })
  && !nodeList.some(function(node) { return isHtmlElement(node, "ul") || ("querySelector" in node && node.querySelector("ul")) })) {
    return "ol";
  }

  // "If every member of node list is either a ul or the child of a ul or the
  // child of an li child of a ul, and none is an ol or an ancestor of an ol,
  // return "ul"."
  if (nodeList.every(function(node) {
    return isHtmlElement(node, "ul")
      || isHtmlElement(node.parentNode, "ul")
      || (isHtmlElement(node.parentNode, "li") && isHtmlElement(node.parentNode.parentNode, "ul"));
  })
  && !nodeList.some(function(node) { return isHtmlElement(node, "ol") || ("querySelector" in node && node.querySelector("ol")) })) {
    return "ul";
  }

  var hasOl = nodeList.some(function(node) {
    return isHtmlElement(node, "ol")
      || isHtmlElement(node.parentNode, "ol")
      || ("querySelector" in node && node.querySelector("ol"))
      || (isHtmlElement(node.parentNode, "li") && isHtmlElement(node.parentNode.parentNode, "ol"));
  });
  var hasUl = nodeList.some(function(node) {
    return isHtmlElement(node, "ul")
      || isHtmlElement(node.parentNode, "ul")
      || ("querySelector" in node && node.querySelector("ul"))
      || (isHtmlElement(node.parentNode, "li") && isHtmlElement(node.parentNode.parentNode, "ul"));
  });
  // "If some member of node list is either an ol or the child or ancestor of
  // an ol or the child of an li child of an ol, and some member of node list
  // is either a ul or the child or ancestor of a ul or the child of an li
  // child of a ul, return "mixed"."
  if (hasOl && hasUl) {
    return "mixed";
  }

  // "If some member of node list is either an ol or the child or ancestor of
  // an ol or the child of an li child of an ol, return "mixed ol"."
  if (hasOl) {
    return "mixed ol";
  }

  // "If some member of node list is either a ul or the child or ancestor of
  // a ul or the child of an li child of a ul, return "mixed ul"."
  if (hasUl) {
    return "mixed ul";
  }

  // "Return "none"."
  return "none";
}

function getAlignmentValue(node) {
  // "While node is neither null nor an Element, or it is an Element but its
  // "display" property has resolved value "inline" or "none", set node to
  // its parent."
  while ((node && node.nodeType != Node.ELEMENT_NODE)
  || (node.nodeType == Node.ELEMENT_NODE
  && ["inline", "none"].indexOf(getComputedStyle(node).display) != -1)) {
    node = node.parentNode;
  }

  // "If node is not an Element, return "left"."
  if (!node || node.nodeType != Node.ELEMENT_NODE) {
    return "left";
  }

  var resolvedValue = getComputedStyle(node).textAlign
    // Hack around browser non-standardness
    .replace(/^-(moz|webkit)-/, "")
    .replace(/^auto$/, "start");

  // "If node's "text-align" property has resolved value "start", return
  // "left" if the directionality of node is "ltr", "right" if it is "rtl"."
  if (resolvedValue == "start") {
    return getDirectionality(node) == "ltr" ? "left" : "right";
  }

  // "If node's "text-align" property has resolved value "end", return
  // "right" if the directionality of node is "ltr", "left" if it is "rtl"."
  if (resolvedValue == "end") {
    return getDirectionality(node) == "ltr" ? "right" : "left";
  }

  // "If node's "text-align" property has resolved value "center", "justify",
  // "left", or "right", return that value."
  if (["center", "justify", "left", "right"].indexOf(resolvedValue) != -1) {
    return resolvedValue;
  }

  // "Return "left"."
  return "left";
}

function getNextEquivalentPoint(node, offset) {
  // "If node's length is zero, return null."
  if (getNodeLength(node) == 0) {
    return null;
  }

  // "If offset is node's length, and node's parent is not null, and node is
  // an inline node, return (node's parent, 1 + node's index)."
  if (offset == getNodeLength(node)
  && node.parentNode
  && isInlineNode(node)) {
    return [node.parentNode, 1 + getNodeIndex(node)];
  }

  // "If node has a child with index offset, and that child's length is not
  // zero, and that child is an inline node, return (that child, 0)."
  if (0 <= offset
  && offset < node.childNodes.length
  && getNodeLength(node.childNodes[offset]) != 0
  && isInlineNode(node.childNodes[offset])) {
    return [node.childNodes[offset], 0];
  }

  // "Return null."
  return null;
}

function getPreviousEquivalentPoint(node, offset) {
  // "If node's length is zero, return null."
  if (getNodeLength(node) == 0) {
    return null;
  }

  // "If offset is 0, and node's parent is not null, and node is an inline
  // node, return (node's parent, node's index)."
  if (offset == 0
  && node.parentNode
  && isInlineNode(node)) {
    return [node.parentNode, getNodeIndex(node)];
  }

  // "If node has a child with index offset − 1, and that child's length is
  // not zero, and that child is an inline node, return (that child, that
  // child's length)."
  if (0 <= offset - 1
  && offset - 1 < node.childNodes.length
  && getNodeLength(node.childNodes[offset - 1]) != 0
  && isInlineNode(node.childNodes[offset - 1])) {
    return [node.childNodes[offset - 1], getNodeLength(node.childNodes[offset - 1])];
  }

  // "Return null."
  return null;
}

function getFirstEquivalentPoint(node, offset) {
  // "While (node, offset)'s previous equivalent point is not null, set
  // (node, offset) to its previous equivalent point."
  var prev;
  while (prev = getPreviousEquivalentPoint(node, offset)) {
    node = prev[0];
    offset = prev[1];
  }

  // "Return (node, offset)."
  return [node, offset];
}

function getLastEquivalentPoint(node, offset) {
  // "While (node, offset)'s next equivalent point is not null, set (node,
  // offset) to its next equivalent point."
  var next;
  while (next = getNextEquivalentPoint(node, offset)) {
    node = next[0];
    offset = next[1];
  }

  // "Return (node, offset)."
  return [node, offset];
}

//@}
///// Block-extending a range /////
//@{

// "A boundary point (node, offset) is a block start point if either node's
// parent is null and offset is zero; or node has a child with index offset −
// 1, and that child is either a visible block node or a visible br."
function isBlockStartPoint(node, offset) {
  return (!node.parentNode && offset == 0)
    || (0 <= offset - 1
    && offset - 1 < node.childNodes.length
    && isVisible(node.childNodes[offset - 1])
    && (isBlockNode(node.childNodes[offset - 1])
    || isHtmlElement(node.childNodes[offset - 1], "br")));
}

// "A boundary point (node, offset) is a block end point if either node's
// parent is null and offset is node's length; or node has a child with index
// offset, and that child is a visible block node."
function isBlockEndPoint(node, offset) {
  return (!node.parentNode && offset == getNodeLength(node))
    || (offset < node.childNodes.length
    && isVisible(node.childNodes[offset])
    && isBlockNode(node.childNodes[offset]));
}

// "A boundary point is a block boundary point if it is either a block start
// point or a block end point."
function isBlockBoundaryPoint(node, offset) {
  return isBlockStartPoint(node, offset)
    || isBlockEndPoint(node, offset);
}

function blockExtend(range) {
  // "Let start node, start offset, end node, and end offset be the start
  // and end nodes and offsets of the range."
  var startNode = range.startContainer;
  var startOffset = range.startOffset;
  var endNode = range.endContainer;
  var endOffset = range.endOffset;

  // "If some ancestor container of start node is an li, set start offset to
  // the index of the last such li in tree order, and set start node to that
  // li's parent."
  var liAncestors = getAncestors(startNode).concat(startNode)
    .filter(function(ancestor) { return isHtmlElement(ancestor, "li") })
    .slice(-1);
  if (liAncestors.length) {
    startOffset = getNodeIndex(liAncestors[0]);
    startNode = liAncestors[0].parentNode;
  }

  // "If (start node, start offset) is not a block start point, repeat the
  // following steps:"
  if (!isBlockStartPoint(startNode, startOffset)) do {
    // "If start offset is zero, set it to start node's index, then set
    // start node to its parent."
    if (startOffset == 0) {
      startOffset = getNodeIndex(startNode);
      startNode = startNode.parentNode;

    // "Otherwise, subtract one from start offset."
    } else {
      startOffset--;
    }

    // "If (start node, start offset) is a block boundary point, break from
    // this loop."
  } while (!isBlockBoundaryPoint(startNode, startOffset));

  // "While start offset is zero and start node's parent is not null, set
  // start offset to start node's index, then set start node to its parent."
  while (startOffset == 0
  && startNode.parentNode) {
    startOffset = getNodeIndex(startNode);
    startNode = startNode.parentNode;
  }

  // "If some ancestor container of end node is an li, set end offset to one
  // plus the index of the last such li in tree order, and set end node to
  // that li's parent."
  var liAncestors = getAncestors(endNode).concat(endNode)
    .filter(function(ancestor) { return isHtmlElement(ancestor, "li") })
    .slice(-1);
  if (liAncestors.length) {
    endOffset = 1 + getNodeIndex(liAncestors[0]);
    endNode = liAncestors[0].parentNode;
  }

  // "If (end node, end offset) is not a block end point, repeat the
  // following steps:"
  if (!isBlockEndPoint(endNode, endOffset)) do {
    // "If end offset is end node's length, set it to one plus end node's
    // index, then set end node to its parent."
    if (endOffset == getNodeLength(endNode)) {
      endOffset = 1 + getNodeIndex(endNode);
      endNode = endNode.parentNode;

    // "Otherwise, add one to end offset.
    } else {
      endOffset++;
    }

    // "If (end node, end offset) is a block boundary point, break from
    // this loop."
  } while (!isBlockBoundaryPoint(endNode, endOffset));

  // "While end offset is end node's length and end node's parent is not
  // null, set end offset to one plus end node's index, then set end node to
  // its parent."
  while (endOffset == getNodeLength(endNode)
  && endNode.parentNode) {
    endOffset = 1 + getNodeIndex(endNode);
    endNode = endNode.parentNode;
  }

  // "Let new range be a new range whose start and end nodes and offsets
  // are start node, start offset, end node, and end offset."
  var newRange = startNode.ownerDocument.createRange();
  newRange.setStart(startNode, startOffset);
  newRange.setEnd(endNode, endOffset);

  // "Return new range."
  return newRange;
}

function followsLineBreak(node) {
  // "Let offset be zero."
  var offset = 0;

  // "While (node, offset) is not a block boundary point:"
  while (!isBlockBoundaryPoint(node, offset)) {
    // "If node has a visible child with index offset minus one, return
    // false."
    if (0 <= offset - 1
    && offset - 1 < node.childNodes.length
    && isVisible(node.childNodes[offset - 1])) {
      return false;
    }

    // "If offset is zero or node has no children, set offset to node's
    // index, then set node to its parent."
    if (offset == 0
    || !node.hasChildNodes()) {
      offset = getNodeIndex(node);
      node = node.parentNode;

    // "Otherwise, set node to its child with index offset minus one, then
    // set offset to node's length."
    } else {
      node = node.childNodes[offset - 1];
      offset = getNodeLength(node);
    }
  }

  // "Return true."
  return true;
}

function precedesLineBreak(node) {
  // "Let offset be node's length."
  var offset = getNodeLength(node);

  // "While (node, offset) is not a block boundary point:"
  while (!isBlockBoundaryPoint(node, offset)) {
    // "If node has a visible child with index offset, return false."
    if (offset < node.childNodes.length
    && isVisible(node.childNodes[offset])) {
      return false;
    }

    // "If offset is node's length or node has no children, set offset to
    // one plus node's index, then set node to its parent."
    if (offset == getNodeLength(node)
    || !node.hasChildNodes()) {
      offset = 1 + getNodeIndex(node);
      node = node.parentNode;

    // "Otherwise, set node to its child with index offset and set offset
    // to zero."
    } else {
      node = node.childNodes[offset];
      offset = 0;
    }
  }

  // "Return true."
  return true;
}

//@}
///// Recording and restoring overrides /////
//@{

function recordCurrentOverrides() {
  // "Let overrides be a list of (string, string or boolean) ordered pairs,
  // initially empty."
  var overrides = [];

  // "If there is a value override for "createLink", add ("createLink", value
  // override for "createLink") to overrides."
  if (getValueOverride("createlink") !== undefined) {
    overrides.push(["createlink", getValueOverride("createlink")]);
  }

  // "For each command in the list "bold", "italic", "strikethrough",
  // "subscript", "superscript", "underline", in order: if there is a state
  // override for command, add (command, command's state override) to
  // overrides."
  ["bold", "italic", "strikethrough", "subscript", "superscript",
  "underline"].forEach(function(command) {
    if (getStateOverride(command) !== undefined) {
      overrides.push([command, getStateOverride(command)]);
    }
  });

  // "For each command in the list "fontName", "fontSize", "foreColor",
  // "hiliteColor", in order: if there is a value override for command, add
  // (command, command's value override) to overrides."
  ["fontname", "fontsize", "forecolor",
  "hilitecolor"].forEach(function(command) {
    if (getValueOverride(command) !== undefined) {
      overrides.push([command, getValueOverride(command)]);
    }
  });

  // "Return overrides."
  return overrides;
}

function recordCurrentStatesAndValues() {
  // "Let overrides be a list of (string, string or boolean) ordered pairs,
  // initially empty."
  var overrides = [];

  // "Let node be the first formattable node effectively contained in the
  // active range, or null if there is none."
  var node = getAllEffectivelyContainedNodes(getActiveRange())
    .filter(isFormattableNode)[0];

  // "If node is null, return overrides."
  if (!node) {
    return overrides;
  }

  // "Add ("createLink", node's effective command value for "createLink") to
  // overrides."
  overrides.push(["createlink", getEffectiveCommandValue(node, "createlink")]);

  // "For each command in the list "bold", "italic", "strikethrough",
  // "subscript", "superscript", "underline", in order: if node's effective
  // command value for command is one of its inline command activated values,
  // add (command, true) to overrides, and otherwise add (command, false) to
  // overrides."
  ["bold", "italic", "strikethrough", "subscript", "superscript",
  "underline"].forEach(function(command) {
    if (commands[command].inlineCommandActivatedValues
    .indexOf(getEffectiveCommandValue(node, command)) != -1) {
      overrides.push([command, true]);
    } else {
      overrides.push([command, false]);
    }
  });

  // "For each command in the list "fontName", "foreColor", "hiliteColor", in
  // order: add (command, command's value) to overrides."
  ["fontname", "fontsize", "forecolor", "hilitecolor"].forEach(function(command) {
    overrides.push([command, commands[command].value()]);
  });

  // "Add ("fontSize", node's effective command value for "fontSize") to
  // overrides."
  overrides.push(["fontsize", getEffectiveCommandValue(node, "fontsize")]);

  // "Return overrides."
  return overrides;
}

function restoreStatesAndValues(overrides) {
  // "Let node be the first formattable node effectively contained in the
  // active range, or null if there is none."
  var node = getAllEffectivelyContainedNodes(getActiveRange())
    .filter(isFormattableNode)[0];

  // "If node is not null, then for each (command, override) pair in
  // overrides, in order:"
  if (node) {
    for (var i = 0; i < overrides.length; i++) {
      var command = overrides[i][0];
      var override = overrides[i][1];

      // "If override is a boolean, and queryCommandState(command)
      // returns something different from override, take the action for
      // command, with value equal to the empty string."
      if (typeof override == "boolean"
      && myQueryCommandState(command) != override) {
        commands[command].action("");

      // "Otherwise, if override is a string, and command is neither
      // "createLink" nor "fontSize", and queryCommandValue(command)
      // returns something not equivalent to override, take the action
      // for command, with value equal to override."
      } else if (typeof override == "string"
      && command != "createlink"
      && command != "fontsize"
      && !areEquivalentValues(command, myQueryCommandValue(command), override)) {
        commands[command].action(override);

      // "Otherwise, if override is a string; and command is
      // "createLink"; and either there is a value override for
      // "createLink" that is not equal to override, or there is no value
      // override for "createLink" and node's effective command value for
      // "createLink" is not equal to override: take the action for
      // "createLink", with value equal to override."
      } else if (typeof override == "string"
      && command == "createlink"
      && (
        (
          getValueOverride("createlink") !== undefined
          && getValueOverride("createlink") !== override
        ) || (
          getValueOverride("createlink") === undefined
          && getEffectiveCommandValue(node, "createlink") !== override
        )
      )) {
        commands.createlink.action(override);

      // "Otherwise, if override is a string; and command is "fontSize";
      // and either there is a value override for "fontSize" that is not
      // equal to override, or there is no value override for "fontSize"
      // and node's effective command value for "fontSize" is not loosely
      // equivalent to override:"
      } else if (typeof override == "string"
      && command == "fontsize"
      && (
        (
          getValueOverride("fontsize") !== undefined
          && getValueOverride("fontsize") !== override
        ) || (
          getValueOverride("fontsize") === undefined
          && !areLooselyEquivalentValues(command, getEffectiveCommandValue(node, "fontsize"), override)
        )
      )) {
        // "Convert override to an integer number of pixels, and set
        // override to the legacy font size for the result."
        override = getLegacyFontSize(override);

        // "Take the action for "fontSize", with value equal to
        // override."
        commands.fontsize.action(override);

      // "Otherwise, continue this loop from the beginning."
      } else {
        continue;
      }

      // "Set node to the first formattable node effectively contained in
      // the active range, if there is one."
      node = getAllEffectivelyContainedNodes(getActiveRange())
        .filter(isFormattableNode)[0]
        || node;
    }

  // "Otherwise, for each (command, override) pair in overrides, in order:"
  } else {
    for (var i = 0; i < overrides.length; i++) {
      var command = overrides[i][0];
      var override = overrides[i][1];

      // "If override is a boolean, set the state override for command to
      // override."
      if (typeof override == "boolean") {
        setStateOverride(command, override);
      }

      // "If override is a string, set the value override for command to
      // override."
      if (typeof override == "string") {
        setValueOverride(command, override);
      }
    }
  }
}

//@}
///// Deleting the selection /////
//@{

// The flags argument is a dictionary that can have blockMerging,
// stripWrappers, and/or direction as keys.
function deleteSelection(flags) {
  if (flags === undefined) {
    flags = {};
  }

  var blockMerging = "blockMerging" in flags ? Boolean(flags.blockMerging) : true;
  var stripWrappers = "stripWrappers" in flags ? Boolean(flags.stripWrappers) : true;
  var direction = "direction" in flags ? flags.direction : "forward";

  // "If the active range is null, abort these steps and do nothing."
  if (!getActiveRange()) {
    return;
  }

  // "Canonicalize whitespace at the active range's start."
  canonicalizeWhitespace(getActiveRange().startContainer, getActiveRange().startOffset);

  // "Canonicalize whitespace at the active range's end."
  canonicalizeWhitespace(getActiveRange().endContainer, getActiveRange().endOffset);

  // "Let (start node, start offset) be the last equivalent point for the
  // active range's start."
  var start = getLastEquivalentPoint(getActiveRange().startContainer, getActiveRange().startOffset);
  var startNode = start[0];
  var startOffset = start[1];

  // "Let (end node, end offset) be the first equivalent point for the active
  // range's end."
  var end = getFirstEquivalentPoint(getActiveRange().endContainer, getActiveRange().endOffset);
  var endNode = end[0];
  var endOffset = end[1];

  // "If (end node, end offset) is not after (start node, start offset):"
  if (getPosition(endNode, endOffset, startNode, startOffset) !== "after") {
    // "If direction is "forward", call collapseToStart() on the context
    // object's Selection."
    //
    // Here and in a few other places, we check rangeCount to work around a
    // WebKit bug: it will sometimes incorrectly remove ranges from the
    // selection if nodes are removed, so collapseToStart() will throw.
    // This will break everything if we're using an actual selection, but
    // if getActiveRange() is really just returning globalRange and that's
    // all we care about, it will work fine.  I only add the extra check
    // for errors I actually hit in testing.
    if (direction == "forward") {
      if (getSelection().rangeCount) {
        getSelection().collapseToStart();
      }
      getActiveRange().collapse(true);

    // "Otherwise, call collapseToEnd() on the context object's Selection."
    } else {
      getSelection().collapseToEnd();
      getActiveRange().collapse(false);
    }

    // "Abort these steps."
    return;
  }

  // "If start node is a Text node and start offset is 0, set start offset to
  // the index of start node, then set start node to its parent."
  if (startNode.nodeType == Node.TEXT_NODE
  && startOffset == 0) {
    startOffset = getNodeIndex(startNode);
    startNode = startNode.parentNode;
  }

  // "If end node is a Text node and end offset is its length, set end offset
  // to one plus the index of end node, then set end node to its parent."
  if (endNode.nodeType == Node.TEXT_NODE
  && endOffset == getNodeLength(endNode)) {
    endOffset = 1 + getNodeIndex(endNode);
    endNode = endNode.parentNode;
  }

  // "Call collapse(start node, start offset) on the context object's
  // Selection."
  getSelection().collapse(startNode, startOffset);
  getActiveRange().setStart(startNode, startOffset);

  // "Call extend(end node, end offset) on the context object's Selection."
  getSelection().extend(endNode, endOffset);
  getActiveRange().setEnd(endNode, endOffset);

  // "Let start block be the active range's start node."
  var startBlock = getActiveRange().startContainer;

  // "While start block's parent is in the same editing host and start block
  // is an inline node, set start block to its parent."
  while (inSameEditingHost(startBlock, startBlock.parentNode)
  && isInlineNode(startBlock)) {
    startBlock = startBlock.parentNode;
  }

  // "If start block is neither a block node nor an editing host, or "span"
  // is not an allowed child of start block, or start block is a td or th,
  // set start block to null."
  if ((!isBlockNode(startBlock) && !isEditingHost(startBlock))
  || !isAllowedChild("span", startBlock)
  || isHtmlElement(startBlock, ["td", "th"])) {
    startBlock = null;
  }

  // "Let end block be the active range's end node."
  var endBlock = getActiveRange().endContainer;

  // "While end block's parent is in the same editing host and end block is
  // an inline node, set end block to its parent."
  while (inSameEditingHost(endBlock, endBlock.parentNode)
  && isInlineNode(endBlock)) {
    endBlock = endBlock.parentNode;
  }

  // "If end block is neither a block node nor an editing host, or "span" is
  // not an allowed child of end block, or end block is a td or th, set end
  // block to null."
  if ((!isBlockNode(endBlock) && !isEditingHost(endBlock))
  || !isAllowedChild("span", endBlock)
  || isHtmlElement(endBlock, ["td", "th"])) {
    endBlock = null;
  }

  // "Record current states and values, and let overrides be the result."
  var overrides = recordCurrentStatesAndValues();

  // "If start node and end node are the same, and start node is an editable
  // Text node:"
  if (startNode == endNode
  && isEditable(startNode)
  && startNode.nodeType == Node.TEXT_NODE) {
    // "Call deleteData(start offset, end offset − start offset) on start
    // node."
    startNode.deleteData(startOffset, endOffset - startOffset);

    // "Canonicalize whitespace at (start node, start offset), with fix
    // collapsed space false."
    canonicalizeWhitespace(startNode, startOffset, false);

    // "If direction is "forward", call collapseToStart() on the context
    // object's Selection."
    if (direction == "forward") {
      if (getSelection().rangeCount) {
        getSelection().collapseToStart();
      }
      getActiveRange().collapse(true);

    // "Otherwise, call collapseToEnd() on the context object's Selection."
    } else {
      getSelection().collapseToEnd();
      getActiveRange().collapse(false);
    }

    // "Restore states and values from overrides."
    restoreStatesAndValues(overrides);

    // "Abort these steps."
    return;
  }

  // "If start node is an editable Text node, call deleteData() on it, with
  // start offset as the first argument and (length of start node − start
  // offset) as the second argument."
  if (isEditable(startNode)
  && startNode.nodeType == Node.TEXT_NODE) {
    startNode.deleteData(startOffset, getNodeLength(startNode) - startOffset);
  }

  // "Let node list be a list of nodes, initially empty."
  //
  // "For each node contained in the active range, append node to node list
  // if the last member of node list (if any) is not an ancestor of node;
  // node is editable; and node is not a thead, tbody, tfoot, tr, th, or td."
  var nodeList = getContainedNodes(getActiveRange(),
    function(node) {
      return isEditable(node)
        && !isHtmlElement(node, ["thead", "tbody", "tfoot", "tr", "th", "td"]);
    }
  );

  // "For each node in node list:"
  for (var i = 0; i < nodeList.length; i++) {
    var node = nodeList[i];

    // "Let parent be the parent of node."
    var parent_ = node.parentNode;

    // "Remove node from parent."
    parent_.removeChild(node);

    // "If the block node of parent has no visible children, and parent is
    // editable or an editing host, call createElement("br") on the context
    // object and append the result as the last child of parent."
    if (![].some.call(getBlockNodeOf(parent_).childNodes, isVisible)
    && (isEditable(parent_) || isEditingHost(parent_))) {
      parent_.appendChild(document.createElement("br"));
    }

    // "If strip wrappers is true or parent is not an ancestor container of
    // start node, while parent is an editable inline node with length 0,
    // let grandparent be the parent of parent, then remove parent from
    // grandparent, then set parent to grandparent."
    if (stripWrappers
    || (!isAncestor(parent_, startNode) && parent_ != startNode)) {
      while (isEditable(parent_)
      && isInlineNode(parent_)
      && getNodeLength(parent_) == 0) {
        var grandparent = parent_.parentNode;
        grandparent.removeChild(parent_);
        parent_ = grandparent;
      }
    }
  }

  // "If end node is an editable Text node, call deleteData(0, end offset) on
  // it."
  if (isEditable(endNode)
  && endNode.nodeType == Node.TEXT_NODE) {
    endNode.deleteData(0, endOffset);
  }

  // "Canonicalize whitespace at the active range's start, with fix collapsed
  // space false."
  canonicalizeWhitespace(getActiveRange().startContainer, getActiveRange().startOffset, false);

  // "Canonicalize whitespace at the active range's end, with fix collapsed
  // space false."
  canonicalizeWhitespace(getActiveRange().endContainer, getActiveRange().endOffset, false);

  // "If block merging is false, or start block or end block is null, or
  // start block is not in the same editing host as end block, or start block
  // and end block are the same:"
  if (!blockMerging
  || !startBlock
  || !endBlock
  || !inSameEditingHost(startBlock, endBlock)
  || startBlock == endBlock) {
    // "If direction is "forward", call collapseToStart() on the context
    // object's Selection."
    if (direction == "forward") {
      if (getSelection().rangeCount) {
        getSelection().collapseToStart();
      }
      getActiveRange().collapse(true);

    // "Otherwise, call collapseToEnd() on the context object's Selection."
    } else {
      if (getSelection().rangeCount) {
        getSelection().collapseToEnd();
      }
      getActiveRange().collapse(false);
    }

    // "Restore states and values from overrides."
    restoreStatesAndValues(overrides);

    // "Abort these steps."
    return;
  }

  // "If start block has one child, which is a collapsed block prop, remove
  // its child from it."
  if (startBlock.children.length == 1
  && isCollapsedBlockProp(startBlock.firstChild)) {
    startBlock.removeChild(startBlock.firstChild);
  }

  // "If start block is an ancestor of end block:"
  if (isAncestor(startBlock, endBlock)) {
    // "Let reference node be end block."
    var referenceNode = endBlock;

    // "While reference node is not a child of start block, set reference
    // node to its parent."
    while (referenceNode.parentNode != startBlock) {
      referenceNode = referenceNode.parentNode;
    }

    // "Call collapse() on the context object's Selection, with first
    // argument start block and second argument the index of reference
    // node."
    getSelection().collapse(startBlock, getNodeIndex(referenceNode));
    getActiveRange().setStart(startBlock, getNodeIndex(referenceNode));
    getActiveRange().collapse(true);

    // "If end block has no children:"
    if (!endBlock.hasChildNodes()) {
      // "While end block is editable and is the only child of its parent
      // and is not a child of start block, let parent equal end block,
      // then remove end block from parent, then set end block to
      // parent."
      while (isEditable(endBlock)
      && endBlock.parentNode.childNodes.length == 1
      && endBlock.parentNode != startBlock) {
        var parent_ = endBlock;
        parent_.removeChild(endBlock);
        endBlock = parent_;
      }

      // "If end block is editable and is not an inline node, and its
      // previousSibling and nextSibling are both inline nodes, call
      // createElement("br") on the context object and insert it into end
      // block's parent immediately after end block."
      if (isEditable(endBlock)
      && !isInlineNode(endBlock)
      && isInlineNode(endBlock.previousSibling)
      && isInlineNode(endBlock.nextSibling)) {
        endBlock.parentNode.insertBefore(document.createElement("br"), endBlock.nextSibling);
      }

      // "If end block is editable, remove it from its parent."
      if (isEditable(endBlock)) {
        endBlock.parentNode.removeChild(endBlock);
      }

      // "Restore states and values from overrides."
      restoreStatesAndValues(overrides);

      // "Abort these steps."
      return;
    }

    // "If end block's firstChild is not an inline node, restore states and
    // values from overrides, then abort these steps."
    if (!isInlineNode(endBlock.firstChild)) {
      restoreStatesAndValues(overrides);
      return;
    }

    // "Let children be a list of nodes, initially empty."
    var children = [];

    // "Append the first child of end block to children."
    children.push(endBlock.firstChild);

    // "While children's last member is not a br, and children's last
    // member's nextSibling is an inline node, append children's last
    // member's nextSibling to children."
    while (!isHtmlElement(children[children.length - 1], "br")
    && isInlineNode(children[children.length - 1].nextSibling)) {
      children.push(children[children.length - 1].nextSibling);
    }

    // "Record the values of children, and let values be the result."
    var values = recordValues(children);

    // "While children's first member's parent is not start block, split
    // the parent of children."
    while (children[0].parentNode != startBlock) {
      splitParent(children);
    }

    // "If children's first member's previousSibling is an editable br,
    // remove that br from its parent."
    if (isEditable(children[0].previousSibling)
    && isHtmlElement(children[0].previousSibling, "br")) {
      children[0].parentNode.removeChild(children[0].previousSibling);
    }

  // "Otherwise, if start block is a descendant of end block:"
  } else if (isDescendant(startBlock, endBlock)) {
    // "Call collapse() on the context object's Selection, with first
    // argument start block and second argument start block's length."
    getSelection().collapse(startBlock, getNodeLength(startBlock));
    getActiveRange().setStart(startBlock, getNodeLength(startBlock));
    getActiveRange().collapse(true);

    // "Let reference node be start block."
    var referenceNode = startBlock;

    // "While reference node is not a child of end block, set reference
    // node to its parent."
    while (referenceNode.parentNode != endBlock) {
      referenceNode = referenceNode.parentNode;
    }

    // "If reference node's nextSibling is an inline node and start block's
    // lastChild is a br, remove start block's lastChild from it."
    if (isInlineNode(referenceNode.nextSibling)
    && isHtmlElement(startBlock.lastChild, "br")) {
      startBlock.removeChild(startBlock.lastChild);
    }

    // "Let nodes to move be a list of nodes, initially empty."
    var nodesToMove = [];

    // "If reference node's nextSibling is neither null nor a block node,
    // append it to nodes to move."
    if (referenceNode.nextSibling
    && !isBlockNode(referenceNode.nextSibling)) {
      nodesToMove.push(referenceNode.nextSibling);
    }

    // "While nodes to move is nonempty and its last member isn't a br and
    // its last member's nextSibling is neither null nor a block node,
    // append its last member's nextSibling to nodes to move."
    if (nodesToMove.length
    && !isHtmlElement(nodesToMove[nodesToMove.length - 1], "br")
    && nodesToMove[nodesToMove.length - 1].nextSibling
    && !isBlockNode(nodesToMove[nodesToMove.length - 1].nextSibling)) {
      nodesToMove.push(nodesToMove[nodesToMove.length - 1].nextSibling);
    }

    // "Record the values of nodes to move, and let values be the result."
    var values = recordValues(nodesToMove);

    // "For each node in nodes to move, append node as the last child of
    // start block, preserving ranges."
    nodesToMove.forEach(function(node) {
      movePreservingRanges(node, startBlock, -1);
    });

  // "Otherwise:"
  } else {
    // "Call collapse() on the context object's Selection, with first
    // argument start block and second argument start block's length."
    getSelection().collapse(startBlock, getNodeLength(startBlock));
    getActiveRange().setStart(startBlock, getNodeLength(startBlock));
    getActiveRange().collapse(true);

    // "If end block's firstChild is an inline node and start block's
    // lastChild is a br, remove start block's lastChild from it."
    if (isInlineNode(endBlock.firstChild)
    && isHtmlElement(startBlock.lastChild, "br")) {
      startBlock.removeChild(startBlock.lastChild);
    }

    // "Record the values of end block's children, and let values be the
    // result."
    var values = recordValues([].slice.call(endBlock.childNodes));

    // "While end block has children, append the first child of end block
    // to start block, preserving ranges."
    while (endBlock.hasChildNodes()) {
      movePreservingRanges(endBlock.firstChild, startBlock, -1);
    }

    // "While end block has no children, let parent be the parent of end
    // block, then remove end block from parent, then set end block to
    // parent."
    while (!endBlock.hasChildNodes()) {
      var parent_ = endBlock.parentNode;
      parent_.removeChild(endBlock);
      endBlock = parent_;
    }
  }

  // "Let ancestor be start block."
  var ancestor = startBlock;

  // "While ancestor has an inclusive ancestor ol in the same editing host
  // whose nextSibling is also an ol in the same editing host, or an
  // inclusive ancestor ul in the same editing host whose nextSibling is also
  // a ul in the same editing host:"
  while (getInclusiveAncestors(ancestor).some(function(node) {
    return inSameEditingHost(ancestor, node)
      && (
        (isHtmlElement(node, "ol") && isHtmlElement(node.nextSibling, "ol"))
        || (isHtmlElement(node, "ul") && isHtmlElement(node.nextSibling, "ul"))
      ) && inSameEditingHost(ancestor, node.nextSibling);
  })) {
    // "While ancestor and its nextSibling are not both ols in the same
    // editing host, and are also not both uls in the same editing host,
    // set ancestor to its parent."
    while (!(
      isHtmlElement(ancestor, "ol")
      && isHtmlElement(ancestor.nextSibling, "ol")
      && inSameEditingHost(ancestor, ancestor.nextSibling)
    ) && !(
      isHtmlElement(ancestor, "ul")
      && isHtmlElement(ancestor.nextSibling, "ul")
      && inSameEditingHost(ancestor, ancestor.nextSibling)
    )) {
      ancestor = ancestor.parentNode;
    }

    // "While ancestor's nextSibling has children, append ancestor's
    // nextSibling's firstChild as the last child of ancestor, preserving
    // ranges."
    while (ancestor.nextSibling.hasChildNodes()) {
      movePreservingRanges(ancestor.nextSibling.firstChild, ancestor, -1);
    }

    // "Remove ancestor's nextSibling from its parent."
    ancestor.parentNode.removeChild(ancestor.nextSibling);
  }

  // "Restore the values from values."
  restoreValues(values);

  // "If start block has no children, call createElement("br") on the context
  // object and append the result as the last child of start block."
  if (!startBlock.hasChildNodes()) {
    startBlock.appendChild(document.createElement("br"));
  }

  // "Remove extraneous line breaks at the end of start block."
  removeExtraneousLineBreaksAtTheEndOf(startBlock);

  // "Restore states and values from overrides."
  restoreStatesAndValues(overrides);
}


//@}
///// Splitting a node list's parent /////
//@{

function splitParent(nodeList) {
  // "Let original parent be the parent of the first member of node list."
  var originalParent = nodeList[0].parentNode;

  // "If original parent is not editable or its parent is null, do nothing
  // and abort these steps."
  if (!isEditable(originalParent)
  || !originalParent.parentNode) {
    return;
  }

  // "If the first child of original parent is in node list, remove
  // extraneous line breaks before original parent."
  if (nodeList.indexOf(originalParent.firstChild) != -1) {
    removeExtraneousLineBreaksBefore(originalParent);
  }

  // "If the first child of original parent is in node list, and original
  // parent follows a line break, set follows line break to true. Otherwise,
  // set follows line break to false."
  var followsLineBreak_ = nodeList.indexOf(originalParent.firstChild) != -1
    && followsLineBreak(originalParent);

  // "If the last child of original parent is in node list, and original
  // parent precedes a line break, set precedes line break to true.
  // Otherwise, set precedes line break to false."
  var precedesLineBreak_ = nodeList.indexOf(originalParent.lastChild) != -1
    && precedesLineBreak(originalParent);

  // "If the first child of original parent is not in node list, but its last
  // child is:"
  if (nodeList.indexOf(originalParent.firstChild) == -1
  && nodeList.indexOf(originalParent.lastChild) != -1) {
    // "For each node in node list, in reverse order, insert node into the
    // parent of original parent immediately after original parent,
    // preserving ranges."
    for (var i = nodeList.length - 1; i >= 0; i--) {
      movePreservingRanges(nodeList[i], originalParent.parentNode, 1 + getNodeIndex(originalParent));
    }

    // "If precedes line break is true, and the last member of node list
    // does not precede a line break, call createElement("br") on the
    // context object and insert the result immediately after the last
    // member of node list."
    if (precedesLineBreak_
    && !precedesLineBreak(nodeList[nodeList.length - 1])) {
      nodeList[nodeList.length - 1].parentNode.insertBefore(document.createElement("br"), nodeList[nodeList.length - 1].nextSibling);
    }

    // "Remove extraneous line breaks at the end of original parent."
    removeExtraneousLineBreaksAtTheEndOf(originalParent);

    // "Abort these steps."
    return;
  }

  // "If the first child of original parent is not in node list:"
  if (nodeList.indexOf(originalParent.firstChild) == -1) {
    // "Let cloned parent be the result of calling cloneNode(false) on
    // original parent."
    var clonedParent = originalParent.cloneNode(false);

    // "If original parent has an id attribute, unset it."
    originalParent.removeAttribute("id");

    // "Insert cloned parent into the parent of original parent immediately
    // before original parent."
    originalParent.parentNode.insertBefore(clonedParent, originalParent);

    // "While the previousSibling of the first member of node list is not
    // null, append the first child of original parent as the last child of
    // cloned parent, preserving ranges."
    while (nodeList[0].previousSibling) {
      movePreservingRanges(originalParent.firstChild, clonedParent, clonedParent.childNodes.length);
    }
  }

  // "For each node in node list, insert node into the parent of original
  // parent immediately before original parent, preserving ranges."
  for (var i = 0; i < nodeList.length; i++) {
    movePreservingRanges(nodeList[i], originalParent.parentNode, getNodeIndex(originalParent));
  }

  // "If follows line break is true, and the first member of node list does
  // not follow a line break, call createElement("br") on the context object
  // and insert the result immediately before the first member of node list."
  if (followsLineBreak_
  && !followsLineBreak(nodeList[0])) {
    nodeList[0].parentNode.insertBefore(document.createElement("br"), nodeList[0]);
  }

  // "If the last member of node list is an inline node other than a br, and
  // the first child of original parent is a br, and original parent is not
  // an inline node, remove the first child of original parent from original
  // parent."
  if (isInlineNode(nodeList[nodeList.length - 1])
  && !isHtmlElement(nodeList[nodeList.length - 1], "br")
  && isHtmlElement(originalParent.firstChild, "br")
  && !isInlineNode(originalParent)) {
    originalParent.removeChild(originalParent.firstChild);
  }

  // "If original parent has no children:"
  if (!originalParent.hasChildNodes()) {
    // "Remove original parent from its parent."
    originalParent.parentNode.removeChild(originalParent);

    // "If precedes line break is true, and the last member of node list
    // does not precede a line break, call createElement("br") on the
    // context object and insert the result immediately after the last
    // member of node list."
    if (precedesLineBreak_
    && !precedesLineBreak(nodeList[nodeList.length - 1])) {
      nodeList[nodeList.length - 1].parentNode.insertBefore(document.createElement("br"), nodeList[nodeList.length - 1].nextSibling);
    }

  // "Otherwise, remove extraneous line breaks before original parent."
  } else {
    removeExtraneousLineBreaksBefore(originalParent);
  }

  // "If node list's last member's nextSibling is null, but its parent is not
  // null, remove extraneous line breaks at the end of node list's last
  // member's parent."
  if (!nodeList[nodeList.length - 1].nextSibling
  && nodeList[nodeList.length - 1].parentNode) {
    removeExtraneousLineBreaksAtTheEndOf(nodeList[nodeList.length - 1].parentNode);
  }
}

// "To remove a node node while preserving its descendants, split the parent of
// node's children if it has any. If it has no children, instead remove it from
// its parent."
function removePreservingDescendants(node) {
  if (node.hasChildNodes()) {
    splitParent([].slice.call(node.childNodes));
  } else {
    node.parentNode.removeChild(node);
  }
}


//@}
///// Canonical space sequences /////
//@{

function canonicalSpaceSequence(n, nonBreakingStart, nonBreakingEnd) {
  // "If n is zero, return the empty string."
  if (n == 0) {
    return "";
  }

  // "If n is one and both non-breaking start and non-breaking end are false,
  // return a single space (U+0020)."
  if (n == 1 && !nonBreakingStart && !nonBreakingEnd) {
    return " ";
  }

  // "If n is one, return a single non-breaking space (U+00A0)."
  if (n == 1) {
    return "\xa0";
  }

  // "Let buffer be the empty string."
  var buffer = "";

  // "If non-breaking start is true, let repeated pair be U+00A0 U+0020.
  // Otherwise, let it be U+0020 U+00A0."
  var repeatedPair;
  if (nonBreakingStart) {
    repeatedPair = "\xa0 ";
  } else {
    repeatedPair = " \xa0";
  }

  // "While n is greater than three, append repeated pair to buffer and
  // subtract two from n."
  while (n > 3) {
    buffer += repeatedPair;
    n -= 2;
  }

  // "If n is three, append a three-element string to buffer depending on
  // non-breaking start and non-breaking end:"
  if (n == 3) {
    buffer +=
      !nonBreakingStart && !nonBreakingEnd ? " \xa0 "
      : nonBreakingStart && !nonBreakingEnd ? "\xa0\xa0 "
      : !nonBreakingStart && nonBreakingEnd ? " \xa0\xa0"
      : nonBreakingStart && nonBreakingEnd ? "\xa0 \xa0"
      : "impossible";

  // "Otherwise, append a two-element string to buffer depending on
  // non-breaking start and non-breaking end:"
  } else {
    buffer +=
      !nonBreakingStart && !nonBreakingEnd ? "\xa0 "
      : nonBreakingStart && !nonBreakingEnd ? "\xa0 "
      : !nonBreakingStart && nonBreakingEnd ? " \xa0"
      : nonBreakingStart && nonBreakingEnd ? "\xa0\xa0"
      : "impossible";
  }

  // "Return buffer."
  return buffer;
}

function canonicalizeWhitespace(node, offset, fixCollapsedSpace) {
  if (fixCollapsedSpace === undefined) {
    // "an optional boolean argument fix collapsed space that defaults to
    // true"
    fixCollapsedSpace = true;
  }

  // "If node is neither editable nor an editing host, abort these steps."
  if (!isEditable(node) && !isEditingHost(node)) {
    return;
  }

  // "Let start node equal node and let start offset equal offset."
  var startNode = node;
  var startOffset = offset;

  // "Repeat the following steps:"
  while (true) {
    // "If start node has a child in the same editing host with index start
    // offset minus one, set start node to that child, then set start
    // offset to start node's length."
    if (0 <= startOffset - 1
    && inSameEditingHost(startNode, startNode.childNodes[startOffset - 1])) {
      startNode = startNode.childNodes[startOffset - 1];
      startOffset = getNodeLength(startNode);

    // "Otherwise, if start offset is zero and start node does not follow a
    // line break and start node's parent is in the same editing host, set
    // start offset to start node's index, then set start node to its
    // parent."
    } else if (startOffset == 0
    && !followsLineBreak(startNode)
    && inSameEditingHost(startNode, startNode.parentNode)) {
      startOffset = getNodeIndex(startNode);
      startNode = startNode.parentNode;

    // "Otherwise, if start node is a Text node and its parent's resolved
    // value for "white-space" is neither "pre" nor "pre-wrap" and start
    // offset is not zero and the (start offset − 1)st element of start
    // node's data is a space (0x0020) or non-breaking space (0x00A0),
    // subtract one from start offset."
    } else if (startNode.nodeType == Node.TEXT_NODE
    && ["pre", "pre-wrap"].indexOf(getComputedStyle(startNode.parentNode).whiteSpace) == -1
    && startOffset != 0
    && /[ \xa0]/.test(startNode.data[startOffset - 1])) {
      startOffset--;

    // "Otherwise, break from this loop."
    } else {
      break;
    }
  }

  // "Let end node equal start node and end offset equal start offset."
  var endNode = startNode;
  var endOffset = startOffset;

  // "Let length equal zero."
  var length = 0;

  // "Let collapse spaces be true if start offset is zero and start node
  // follows a line break, otherwise false."
  var collapseSpaces = startOffset == 0 && followsLineBreak(startNode);

  // "Repeat the following steps:"
  while (true) {
    // "If end node has a child in the same editing host with index end
    // offset, set end node to that child, then set end offset to zero."
    if (endOffset < endNode.childNodes.length
    && inSameEditingHost(endNode, endNode.childNodes[endOffset])) {
      endNode = endNode.childNodes[endOffset];
      endOffset = 0;

    // "Otherwise, if end offset is end node's length and end node does not
    // precede a line break and end node's parent is in the same editing
    // host, set end offset to one plus end node's index, then set end node
    // to its parent."
    } else if (endOffset == getNodeLength(endNode)
    && !precedesLineBreak(endNode)
    && inSameEditingHost(endNode, endNode.parentNode)) {
      endOffset = 1 + getNodeIndex(endNode);
      endNode = endNode.parentNode;

    // "Otherwise, if end node is a Text node and its parent's resolved
    // value for "white-space" is neither "pre" nor "pre-wrap" and end
    // offset is not end node's length and the end offsetth element of
    // end node's data is a space (0x0020) or non-breaking space (0x00A0):"
    } else if (endNode.nodeType == Node.TEXT_NODE
    && ["pre", "pre-wrap"].indexOf(getComputedStyle(endNode.parentNode).whiteSpace) == -1
    && endOffset != getNodeLength(endNode)
    && /[ \xa0]/.test(endNode.data[endOffset])) {
      // "If fix collapsed space is true, and collapse spaces is true,
      // and the end offsetth code unit of end node's data is a space
      // (0x0020): call deleteData(end offset, 1) on end node, then
      // continue this loop from the beginning."
      if (fixCollapsedSpace
      && collapseSpaces
      && " " == endNode.data[endOffset]) {
        endNode.deleteData(endOffset, 1);
        continue;
      }

      // "Set collapse spaces to true if the end offsetth element of end
      // node's data is a space (0x0020), false otherwise."
      collapseSpaces = " " == endNode.data[endOffset];

      // "Add one to end offset."
      endOffset++;

      // "Add one to length."
      length++;

    // "Otherwise, break from this loop."
    } else {
      break;
    }
  }

  // "If fix collapsed space is true, then while (start node, start offset)
  // is before (end node, end offset):"
  if (fixCollapsedSpace) {
    while (getPosition(startNode, startOffset, endNode, endOffset) == "before") {
      // "If end node has a child in the same editing host with index end
      // offset − 1, set end node to that child, then set end offset to end
      // node's length."
      if (0 <= endOffset - 1
      && endOffset - 1 < endNode.childNodes.length
      && inSameEditingHost(endNode, endNode.childNodes[endOffset - 1])) {
        endNode = endNode.childNodes[endOffset - 1];
        endOffset = getNodeLength(endNode);

      // "Otherwise, if end offset is zero and end node's parent is in the
      // same editing host, set end offset to end node's index, then set end
      // node to its parent."
      } else if (endOffset == 0
      && inSameEditingHost(endNode, endNode.parentNode)) {
        endOffset = getNodeIndex(endNode);
        endNode = endNode.parentNode;

      // "Otherwise, if end node is a Text node and its parent's resolved
      // value for "white-space" is neither "pre" nor "pre-wrap" and end
      // offset is end node's length and the last code unit of end node's
      // data is a space (0x0020) and end node precedes a line break:"
      } else if (endNode.nodeType == Node.TEXT_NODE
      && ["pre", "pre-wrap"].indexOf(getComputedStyle(endNode.parentNode).whiteSpace) == -1
      && endOffset == getNodeLength(endNode)
      && endNode.data[endNode.data.length - 1] == " "
      && precedesLineBreak(endNode)) {
        // "Subtract one from end offset."
        endOffset--;

        // "Subtract one from length."
        length--;

        // "Call deleteData(end offset, 1) on end node."
        endNode.deleteData(endOffset, 1);

      // "Otherwise, break from this loop."
      } else {
        break;
      }
    }
  }

  // "Let replacement whitespace be the canonical space sequence of length
  // length. non-breaking start is true if start offset is zero and start
  // node follows a line break, and false otherwise. non-breaking end is true
  // if end offset is end node's length and end node precedes a line break,
  // and false otherwise."
  var replacementWhitespace = canonicalSpaceSequence(length,
    startOffset == 0 && followsLineBreak(startNode),
    endOffset == getNodeLength(endNode) && precedesLineBreak(endNode));

  // "While (start node, start offset) is before (end node, end offset):"
  while (getPosition(startNode, startOffset, endNode, endOffset) == "before") {
    // "If start node has a child with index start offset, set start node
    // to that child, then set start offset to zero."
    if (startOffset < startNode.childNodes.length) {
      startNode = startNode.childNodes[startOffset];
      startOffset = 0;

    // "Otherwise, if start node is not a Text node or if start offset is
    // start node's length, set start offset to one plus start node's
    // index, then set start node to its parent."
    } else if (startNode.nodeType != Node.TEXT_NODE
    || startOffset == getNodeLength(startNode)) {
      startOffset = 1 + getNodeIndex(startNode);
      startNode = startNode.parentNode;

    // "Otherwise:"
    } else {
      // "Remove the first element from replacement whitespace, and let
      // element be that element."
      var element = replacementWhitespace[0];
      replacementWhitespace = replacementWhitespace.slice(1);

      // "If element is not the same as the start offsetth element of
      // start node's data:"
      if (element != startNode.data[startOffset]) {
        // "Call insertData(start offset, element) on start node."
        startNode.insertData(startOffset, element);

        // "Call deleteData(start offset + 1, 1) on start node."
        startNode.deleteData(startOffset + 1, 1);
      }

      // "Add one to start offset."
      startOffset++;
    }
  }
}


//@}
///// Indenting and outdenting /////
//@{

function indentNodes(nodeList) {
  // "If node list is empty, do nothing and abort these steps."
  if (!nodeList.length) {
    return;
  }

  // "Let first node be the first member of node list."
  var firstNode = nodeList[0];

  // "If first node's parent is an ol or ul:"
  if (isHtmlElement(firstNode.parentNode, ["OL", "UL"])) {
    // "Let tag be the local name of the parent of first node."
    var tag = firstNode.parentNode.tagName;

    // "Wrap node list, with sibling criteria returning true for an HTML
    // element with local name tag and false otherwise, and new parent
    // instructions returning the result of calling createElement(tag) on
    // the ownerDocument of first node."
    wrap(nodeList,
      function(node) { return isHtmlElement(node, tag) },
      function() { return firstNode.ownerDocument.createElement(tag) });

    // "Abort these steps."
    return;
  }

  // "Wrap node list, with sibling criteria returning true for a simple
  // indentation element and false otherwise, and new parent instructions
  // returning the result of calling createElement("blockquote") on the
  // ownerDocument of first node. Let new parent be the result."
  var newParent = wrap(nodeList,
    function(node) { return isSimpleIndentationElement(node) },
    function() { return firstNode.ownerDocument.createElement("blockquote") });

  // "Fix disallowed ancestors of new parent."
  fixDisallowedAncestors(newParent);
}

function outdentNode(node) {
  // "If node is not editable, abort these steps."
  if (!isEditable(node)) {
    return;
  }

  // "If node is a simple indentation element, remove node, preserving its
  // descendants.  Then abort these steps."
  if (isSimpleIndentationElement(node)) {
    removePreservingDescendants(node);
    return;
  }

  // "If node is an indentation element:"
  if (isIndentationElement(node)) {
    // "Unset the dir attribute of node, if any."
    node.removeAttribute("dir");

    // "Unset the margin, padding, and border CSS properties of node."
    node.style.margin = "";
    node.style.padding = "";
    node.style.border = "";
    if (node.getAttribute("style") == ""
    // Crazy WebKit bug: https://bugs.webkit.org/show_bug.cgi?id=68551
    || node.getAttribute("style") == "border-width: initial; border-color: initial; ") {
      node.removeAttribute("style");
    }

    // "Set the tag name of node to "div"."
    setTagName(node, "div");

    // "Abort these steps."
    return;
  }

  // "Let current ancestor be node's parent."
  var currentAncestor = node.parentNode;

  // "Let ancestor list be a list of nodes, initially empty."
  var ancestorList = [];

  // "While current ancestor is an editable Element that is neither a simple
  // indentation element nor an ol nor a ul, append current ancestor to
  // ancestor list and then set current ancestor to its parent."
  while (isEditable(currentAncestor)
  && currentAncestor.nodeType == Node.ELEMENT_NODE
  && !isSimpleIndentationElement(currentAncestor)
  && !isHtmlElement(currentAncestor, ["ol", "ul"])) {
    ancestorList.push(currentAncestor);
    currentAncestor = currentAncestor.parentNode;
  }

  // "If current ancestor is not an editable simple indentation element:"
  if (!isEditable(currentAncestor)
  || !isSimpleIndentationElement(currentAncestor)) {
    // "Let current ancestor be node's parent."
    currentAncestor = node.parentNode;

    // "Let ancestor list be the empty list."
    ancestorList = [];

    // "While current ancestor is an editable Element that is neither an
    // indentation element nor an ol nor a ul, append current ancestor to
    // ancestor list and then set current ancestor to its parent."
    while (isEditable(currentAncestor)
    && currentAncestor.nodeType == Node.ELEMENT_NODE
    && !isIndentationElement(currentAncestor)
    && !isHtmlElement(currentAncestor, ["ol", "ul"])) {
      ancestorList.push(currentAncestor);
      currentAncestor = currentAncestor.parentNode;
    }
  }

  // "If node is an ol or ul and current ancestor is not an editable
  // indentation element:"
  if (isHtmlElement(node, ["OL", "UL"])
  && (!isEditable(currentAncestor)
  || !isIndentationElement(currentAncestor))) {
    // "Unset the reversed, start, and type attributes of node, if any are
    // set."
    node.removeAttribute("reversed");
    node.removeAttribute("start");
    node.removeAttribute("type");

    // "Let children be the children of node."
    var children = [].slice.call(node.childNodes);

    // "If node has attributes, and its parent is not an ol or ul, set the
    // tag name of node to "div"."
    if (node.attributes.length
    && !isHtmlElement(node.parentNode, ["OL", "UL"])) {
      setTagName(node, "div");

    // "Otherwise:"
    } else {
      // "Record the values of node's children, and let values be the
      // result."
      var values = recordValues([].slice.call(node.childNodes));

      // "Remove node, preserving its descendants."
      removePreservingDescendants(node);

      // "Restore the values from values."
      restoreValues(values);
    }

    // "Fix disallowed ancestors of each member of children."
    for (var i = 0; i < children.length; i++) {
      fixDisallowedAncestors(children[i]);
    }

    // "Abort these steps."
    return;
  }

  // "If current ancestor is not an editable indentation element, abort these
  // steps."
  if (!isEditable(currentAncestor)
  || !isIndentationElement(currentAncestor)) {
    return;
  }

  // "Append current ancestor to ancestor list."
  ancestorList.push(currentAncestor);

  // "Let original ancestor be current ancestor."
  var originalAncestor = currentAncestor;

  // "While ancestor list is not empty:"
  while (ancestorList.length) {
    // "Let current ancestor be the last member of ancestor list."
    //
    // "Remove the last member of ancestor list."
    currentAncestor = ancestorList.pop();

    // "Let target be the child of current ancestor that is equal to either
    // node or the last member of ancestor list."
    var target = node.parentNode == currentAncestor
      ? node
      : ancestorList[ancestorList.length - 1];

    // "If target is an inline node that is not a br, and its nextSibling
    // is a br, remove target's nextSibling from its parent."
    if (isInlineNode(target)
    && !isHtmlElement(target, "BR")
    && isHtmlElement(target.nextSibling, "BR")) {
      target.parentNode.removeChild(target.nextSibling);
    }

    // "Let preceding siblings be the preceding siblings of target, and let
    // following siblings be the following siblings of target."
    var precedingSiblings = [].slice.call(currentAncestor.childNodes, 0, getNodeIndex(target));
    var followingSiblings = [].slice.call(currentAncestor.childNodes, 1 + getNodeIndex(target));

    // "Indent preceding siblings."
    indentNodes(precedingSiblings);

    // "Indent following siblings."
    indentNodes(followingSiblings);
  }

  // "Outdent original ancestor."
  outdentNode(originalAncestor);
}


//@}
///// Toggling lists /////
//@{

function toggleLists(tagName) {
  // "Let mode be "disable" if the selection's list state is tag name, and
  // "enable" otherwise."
  var mode = getSelectionListState() == tagName ? "disable" : "enable";

  var range = getActiveRange();
  tagName = tagName.toUpperCase();

  // "Let other tag name be "ol" if tag name is "ul", and "ul" if tag name is
  // "ol"."
  var otherTagName = tagName == "OL" ? "UL" : "OL";

  // "Let items be a list of all lis that are ancestor containers of the
  // range's start and/or end node."
  //
  // It's annoying to get this in tree order using functional stuff without
  // doing getDescendants(document), which is slow, so I do it imperatively.
  var items = [];
  (function(){
    for (
      var ancestorContainer = range.endContainer;
      ancestorContainer != range.commonAncestorContainer;
      ancestorContainer = ancestorContainer.parentNode
    ) {
      if (isHtmlElement(ancestorContainer, "li")) {
        items.unshift(ancestorContainer);
      }
    }
    for (
      var ancestorContainer = range.startContainer;
      ancestorContainer;
      ancestorContainer = ancestorContainer.parentNode
    ) {
      if (isHtmlElement(ancestorContainer, "li")) {
        items.unshift(ancestorContainer);
      }
    }
  })();

  // "For each item in items, normalize sublists of item."
  items.forEach(normalizeSublists);

  // "Block-extend the range, and let new range be the result."
  var newRange = blockExtend(range);

  // "If mode is "enable", then let lists to convert consist of every
  // editable HTML element with local name other tag name that is contained
  // in new range, and for every list in lists to convert:"
  if (mode == "enable") {
    getAllContainedNodes(newRange, function(node) {
      return isEditable(node)
        && isHtmlElement(node, otherTagName);
    }).forEach(function(list) {
      // "If list's previousSibling or nextSibling is an editable HTML
      // element with local name tag name:"
      if ((isEditable(list.previousSibling) && isHtmlElement(list.previousSibling, tagName))
      || (isEditable(list.nextSibling) && isHtmlElement(list.nextSibling, tagName))) {
        // "Let children be list's children."
        var children = [].slice.call(list.childNodes);

        // "Record the values of children, and let values be the
        // result."
        var values = recordValues(children);

        // "Split the parent of children."
        splitParent(children);

        // "Wrap children, with sibling criteria returning true for an
        // HTML element with local name tag name and false otherwise."
        wrap(children, function(node) { return isHtmlElement(node, tagName) });

        // "Restore the values from values."
        restoreValues(values);

      // "Otherwise, set the tag name of list to tag name."
      } else {
        setTagName(list, tagName);
      }
    });
  }

  // "Let node list be a list of nodes, initially empty."
  //
  // "For each node node contained in new range, if node is editable; the
  // last member of node list (if any) is not an ancestor of node; node
  // is not an indentation element; and either node is an ol or ul, or its
  // parent is an ol or ul, or it is an allowed child of "li"; then append
  // node to node list."
  var nodeList = getContainedNodes(newRange, function(node) {
    return isEditable(node)
    && !isIndentationElement(node)
    && (isHtmlElement(node, ["OL", "UL"])
    || isHtmlElement(node.parentNode, ["OL", "UL"])
    || isAllowedChild(node, "li"));
  });

  // "If mode is "enable", remove from node list any ol or ul whose parent is
  // not also an ol or ul."
  if (mode == "enable") {
    nodeList = nodeList.filter(function(node) {
      return !isHtmlElement(node, ["ol", "ul"])
        || isHtmlElement(node.parentNode, ["ol", "ul"]);
    });
  }

  // "If mode is "disable", then while node list is not empty:"
  if (mode == "disable") {
    while (nodeList.length) {
      // "Let sublist be an empty list of nodes."
      var sublist = [];

      // "Remove the first member from node list and append it to
      // sublist."
      sublist.push(nodeList.shift());

      // "If the first member of sublist is an HTML element with local
      // name tag name, outdent it and continue this loop from the
      // beginning."
      if (isHtmlElement(sublist[0], tagName)) {
        outdentNode(sublist[0]);
        continue;
      }

      // "While node list is not empty, and the first member of node list
      // is the nextSibling of the last member of sublist and is not an
      // HTML element with local name tag name, remove the first member
      // from node list and append it to sublist."
      while (nodeList.length
      && nodeList[0] == sublist[sublist.length - 1].nextSibling
      && !isHtmlElement(nodeList[0], tagName)) {
        sublist.push(nodeList.shift());
      }

      // "Record the values of sublist, and let values be the result."
      var values = recordValues(sublist);

      // "Split the parent of sublist."
      splitParent(sublist);

      // "Fix disallowed ancestors of each member of sublist."
      for (var i = 0; i < sublist.length; i++) {
        fixDisallowedAncestors(sublist[i]);
      }

      // "Restore the values from values."
      restoreValues(values);
    }

  // "Otherwise, while node list is not empty:"
  } else {
    while (nodeList.length) {
      // "Let sublist be an empty list of nodes."
      var sublist = [];

      // "While either sublist is empty, or node list is not empty and
      // its first member is the nextSibling of sublist's last member:"
      while (!sublist.length
      || (nodeList.length
      && nodeList[0] == sublist[sublist.length - 1].nextSibling)) {
        // "If node list's first member is a p or div, set the tag name
        // of node list's first member to "li", and append the result
        // to sublist. Remove the first member from node list."
        if (isHtmlElement(nodeList[0], ["p", "div"])) {
          sublist.push(setTagName(nodeList[0], "li"));
          nodeList.shift();

        // "Otherwise, if the first member of node list is an li or ol
        // or ul, remove it from node list and append it to sublist."
        } else if (isHtmlElement(nodeList[0], ["li", "ol", "ul"])) {
          sublist.push(nodeList.shift());

        // "Otherwise:"
        } else {
          // "Let nodes to wrap be a list of nodes, initially empty."
          var nodesToWrap = [];

          // "While nodes to wrap is empty, or node list is not empty
          // and its first member is the nextSibling of nodes to
          // wrap's last member and the first member of node list is
          // an inline node and the last member of nodes to wrap is
          // an inline node other than a br, remove the first member
          // from node list and append it to nodes to wrap."
          while (!nodesToWrap.length
          || (nodeList.length
          && nodeList[0] == nodesToWrap[nodesToWrap.length - 1].nextSibling
          && isInlineNode(nodeList[0])
          && isInlineNode(nodesToWrap[nodesToWrap.length - 1])
          && !isHtmlElement(nodesToWrap[nodesToWrap.length - 1], "br"))) {
            nodesToWrap.push(nodeList.shift());
          }

          // "Wrap nodes to wrap, with new parent instructions
          // returning the result of calling createElement("li") on
          // the context object. Append the result to sublist."
          sublist.push(wrap(nodesToWrap,
            undefined,
            function() { return document.createElement("li") }));
        }
      }

      // "If sublist's first member's parent is an HTML element with
      // local name tag name, or if every member of sublist is an ol or
      // ul, continue this loop from the beginning."
      if (isHtmlElement(sublist[0].parentNode, tagName)
      || sublist.every(function(node) { return isHtmlElement(node, ["ol", "ul"]) })) {
        continue;
      }

      // "If sublist's first member's parent is an HTML element with
      // local name other tag name:"
      if (isHtmlElement(sublist[0].parentNode, otherTagName)) {
        // "Record the values of sublist, and let values be the
        // result."
        var values = recordValues(sublist);

        // "Split the parent of sublist."
        splitParent(sublist);

        // "Wrap sublist, with sibling criteria returning true for an
        // HTML element with local name tag name and false otherwise,
        // and new parent instructions returning the result of calling
        // createElement(tag name) on the context object."
        wrap(sublist,
          function(node) { return isHtmlElement(node, tagName) },
          function() { return document.createElement(tagName) });

        // "Restore the values from values."
        restoreValues(values);

        // "Continue this loop from the beginning."
        continue;
      }

      // "Wrap sublist, with sibling criteria returning true for an HTML
      // element with local name tag name and false otherwise, and new
      // parent instructions being the following:"
      // . . .
      // "Fix disallowed ancestors of the previous step's result."
      fixDisallowedAncestors(wrap(sublist,
        function(node) { return isHtmlElement(node, tagName) },
        function() {
          // "If sublist's first member's parent is not an editable
          // simple indentation element, or sublist's first member's
          // parent's previousSibling is not an editable HTML element
          // with local name tag name, call createElement(tag name)
          // on the context object and return the result."
          if (!isEditable(sublist[0].parentNode)
          || !isSimpleIndentationElement(sublist[0].parentNode)
          || !isEditable(sublist[0].parentNode.previousSibling)
          || !isHtmlElement(sublist[0].parentNode.previousSibling, tagName)) {
            return document.createElement(tagName);
          }

          // "Let list be sublist's first member's parent's
          // previousSibling."
          var list = sublist[0].parentNode.previousSibling;

          // "Normalize sublists of list's lastChild."
          normalizeSublists(list.lastChild);

          // "If list's lastChild is not an editable HTML element
          // with local name tag name, call createElement(tag name)
          // on the context object, and append the result as the last
          // child of list."
          if (!isEditable(list.lastChild)
          || !isHtmlElement(list.lastChild, tagName)) {
            list.appendChild(document.createElement(tagName));
          }

          // "Return the last child of list."
          return list.lastChild;
        }
      ));
    }
  }
}


//@}
///// Justifying the selection /////
//@{

function justifySelection(alignment) {
  // "Block-extend the active range, and let new range be the result."
  var newRange = blockExtend(globalRange);

  // "Let element list be a list of all editable Elements contained in new
  // range that either has an attribute in the HTML namespace whose local
  // name is "align", or has a style attribute that sets "text-align", or is
  // a center."
  var elementList = getAllContainedNodes(newRange, function(node) {
    return node.nodeType == Node.ELEMENT_NODE
      && isEditable(node)
      // Ignoring namespaces here
      && (
        node.hasAttribute("align")
        || node.style.textAlign != ""
        || isHtmlElement(node, "center")
      );
  });

  // "For each element in element list:"
  for (var i = 0; i < elementList.length; i++) {
    var element = elementList[i];

    // "If element has an attribute in the HTML namespace whose local name
    // is "align", remove that attribute."
    element.removeAttribute("align");

    // "Unset the CSS property "text-align" on element, if it's set by a
    // style attribute."
    element.style.textAlign = "";
    if (element.getAttribute("style") == "") {
      element.removeAttribute("style");
    }

    // "If element is a div or span or center with no attributes, remove
    // it, preserving its descendants."
    if (isHtmlElement(element, ["div", "span", "center"])
    && !element.attributes.length) {
      removePreservingDescendants(element);
    }

    // "If element is a center with one or more attributes, set the tag
    // name of element to "div"."
    if (isHtmlElement(element, "center")
    && element.attributes.length) {
      setTagName(element, "div");
    }
  }

  // "Block-extend the active range, and let new range be the result."
  newRange = blockExtend(globalRange);

  // "Let node list be a list of nodes, initially empty."
  var nodeList = [];

  // "For each node node contained in new range, append node to node list if
  // the last member of node list (if any) is not an ancestor of node; node
  // is editable; node is an allowed child of "div"; and node's alignment
  // value is not alignment."
  nodeList = getContainedNodes(newRange, function(node) {
    return isEditable(node)
      && isAllowedChild(node, "div")
      && getAlignmentValue(node) != alignment;
  });

  // "While node list is not empty:"
  while (nodeList.length) {
    // "Let sublist be a list of nodes, initially empty."
    var sublist = [];

    // "Remove the first member of node list and append it to sublist."
    sublist.push(nodeList.shift());

    // "While node list is not empty, and the first member of node list is
    // the nextSibling of the last member of sublist, remove the first
    // member of node list and append it to sublist."
    while (nodeList.length
    && nodeList[0] == sublist[sublist.length - 1].nextSibling) {
      sublist.push(nodeList.shift());
    }

    // "Wrap sublist. Sibling criteria returns true for any div that has
    // one or both of the following two attributes and no other attributes,
    // and false otherwise:"
    //
    //   * "An align attribute whose value is an ASCII case-insensitive
    //     match for alignment.
    //   * "A style attribute which sets exactly one CSS property
    //     (including unrecognized or invalid attributes), which is
    //     "text-align", which is set to alignment.
    //
    // "New parent instructions are to call createElement("div") on the
    // context object, then set its CSS property "text-align" to alignment
    // and return the result."
    wrap(sublist,
      function(node) {
        return isHtmlElement(node, "div")
          && [].every.call(node.attributes, function(attr) {
            return (attr.name == "align" && attr.value.toLowerCase() == alignment)
              || (attr.name == "style" && node.style.length == 1 && node.style.textAlign == alignment);
          });
      },
      function() {
        var newParent = document.createElement("div");
        newParent.setAttribute("style", "text-align: " + alignment);
        return newParent;
      }
    );
  }
}


//@}
///// Automatic linking /////
//@{
// "An autolinkable URL is a string of the following form:"
var autolinkableUrlRegexp =
  // "Either a string matching the scheme pattern from RFC 3986 section 3.1
  // followed by the literal string ://, or the literal string mailto:;
  // followed by"
  //
  // From the RFC: scheme      = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
  "([a-zA-Z][a-zA-Z0-9+.-]*://|mailto:)"
  // "Zero or more characters other than space characters; followed by"
  + "[^ \t\n\f\r]*"
  // "A character that is not one of the ASCII characters !"'(),-.:;<>[]`{}."
  + "[^!\"'(),\\-.:;<>[\\]`{}]";

// "A valid e-mail address is a string that matches the ABNF production 1*(
// atext / "." ) "@" ldh-str *( "." ldh-str ) where atext is defined in RFC
// 5322 section 3.2.3, and ldh-str is defined in RFC 1034 section 3.5."
//
// atext: ALPHA / DIGIT / "!" / "#" / "$" / "%" / "&" / "'" / "*" / "+" / "-" /
// "/" / "=" / "?" / "^" / "_" / "`" / "{" / "|" / "}" / "~"
//
//<ldh-str> ::= <let-dig-hyp> | <let-dig-hyp> <ldh-str>
//<let-dig-hyp> ::= <let-dig> | "-"
//<let-dig> ::= <letter> | <digit>
var validEmailRegexp =
  "[a-zA-Z0-9!#$%&'*+\\-/=?^_`{|}~.]+@[a-zA-Z0-9-]+(\.[a-zA-Z0-9-]+)*";

function autolink(node, endOffset) {
  // "While (node, end offset)'s previous equivalent point is not null, set
  // it to its previous equivalent point."
  while (getPreviousEquivalentPoint(node, endOffset)) {
    var prev = getPreviousEquivalentPoint(node, endOffset);
    node = prev[0];
    endOffset = prev[1];
  }

  // "If node is not a Text node, or has an a ancestor, do nothing and abort
  // these steps."
  if (node.nodeType != Node.TEXT_NODE
  || getAncestors(node).some(function(ancestor) { return isHtmlElement(ancestor, "a") })) {
    return;
  }

  // "Let search be the largest substring of node's data whose end is end
  // offset and that contains no space characters."
  var search = /[^ \t\n\f\r]*$/.exec(node.substringData(0, endOffset))[0];

  // "If some substring of search is an autolinkable URL:"
  if (new RegExp(autolinkableUrlRegexp).test(search)) {
    // "While there is no substring of node's data ending at end offset
    // that is an autolinkable URL, decrement end offset."
    while (!(new RegExp(autolinkableUrlRegexp + "$").test(node.substringData(0, endOffset)))) {
      endOffset--;
    }

    // "Let start offset be the start index of the longest substring of
    // node's data that is an autolinkable URL ending at end offset."
    var startOffset = new RegExp(autolinkableUrlRegexp + "$").exec(node.substringData(0, endOffset)).index;

    // "Let href be the substring of node's data starting at start offset
    // and ending at end offset."
    var href = node.substringData(startOffset, endOffset - startOffset);

  // "Otherwise, if some substring of search is a valid e-mail address:"
  } else if (new RegExp(validEmailRegexp).test(search)) {
    // "While there is no substring of node's data ending at end offset
    // that is a valid e-mail address, decrement end offset."
    while (!(new RegExp(validEmailRegexp + "$").test(node.substringData(0, endOffset)))) {
      endOffset--;
    }

    // "Let start offset be the start index of the longest substring of
    // node's data that is a valid e-mail address ending at end offset."
    var startOffset = new RegExp(validEmailRegexp + "$").exec(node.substringData(0, endOffset)).index;

    // "Let href be "mailto:" concatenated with the substring of node's
    // data starting at start offset and ending at end offset."
    var href = "mailto:" + node.substringData(startOffset, endOffset - startOffset);

  // "Otherwise, do nothing and abort these steps."
  } else {
    return;
  }

  // "Let original range be the active range."
  var originalRange = getActiveRange();

  // "Create a new range with start (node, start offset) and end (node, end
  // offset), and set the context object's selection's range to it."
  var newRange = document.createRange();
  newRange.setStart(node, startOffset);
  newRange.setEnd(node, endOffset);
  getSelection().removeAllRanges();
  getSelection().addRange(newRange);
  globalRange = newRange;

  // "Take the action for "createLink", with value equal to href."
  commands.createlink.action(href);

  // "Set the context object's selection's range to original range."
  getSelection().removeAllRanges();
  getSelection().addRange(originalRange);
  globalRange = originalRange;
}
//@}
///// The delete command /////
//@{
commands["delete"] = {
  preservesOverrides: true,
  action: function() {
    // "If the active range is not collapsed, delete the selection and
    // return true."
    if (!getActiveRange().collapsed) {
      deleteSelection();
      return true;
    }

    // "Canonicalize whitespace at the active range's start."
    canonicalizeWhitespace(getActiveRange().startContainer, getActiveRange().startOffset);

    // "Let node and offset be the active range's start node and offset."
    var node = getActiveRange().startContainer;
    var offset = getActiveRange().startOffset;

    // "Repeat the following steps:"
    while (true) {
      // "If offset is zero and node's previousSibling is an editable
      // invisible node, remove node's previousSibling from its parent."
      if (offset == 0
      && isEditable(node.previousSibling)
      && isInvisible(node.previousSibling)) {
        node.parentNode.removeChild(node.previousSibling);

      // "Otherwise, if node has a child with index offset − 1 and that
      // child is an editable invisible node, remove that child from
      // node, then subtract one from offset."
      } else if (0 <= offset - 1
      && offset - 1 < node.childNodes.length
      && isEditable(node.childNodes[offset - 1])
      && isInvisible(node.childNodes[offset - 1])) {
        node.removeChild(node.childNodes[offset - 1]);
        offset--;

      // "Otherwise, if offset is zero and node is an inline node, or if
      // node is an invisible node, set offset to the index of node, then
      // set node to its parent."
      } else if ((offset == 0
      && isInlineNode(node))
      || isInvisible(node)) {
        offset = getNodeIndex(node);
        node = node.parentNode;

      // "Otherwise, if node has a child with index offset − 1 and that
      // child is an editable a, remove that child from node, preserving
      // its descendants. Then return true."
      } else if (0 <= offset - 1
      && offset - 1 < node.childNodes.length
      && isEditable(node.childNodes[offset - 1])
      && isHtmlElement(node.childNodes[offset - 1], "a")) {
        removePreservingDescendants(node.childNodes[offset - 1]);
        return true;

      // "Otherwise, if node has a child with index offset − 1 and that
      // child is not a block node or a br or an img, set node to that
      // child, then set offset to the length of node."
      } else if (0 <= offset - 1
      && offset - 1 < node.childNodes.length
      && !isBlockNode(node.childNodes[offset - 1])
      && !isHtmlElement(node.childNodes[offset - 1], ["br", "img"])) {
        node = node.childNodes[offset - 1];
        offset = getNodeLength(node);

      // "Otherwise, break from this loop."
      } else {
        break;
      }
    }

    // "If node is a Text node and offset is not zero, or if node is a
    // block node that has a child with index offset − 1 and that child is
    // a br or hr or img:"
    if ((node.nodeType == Node.TEXT_NODE
    && offset != 0)
    || (isBlockNode(node)
    && 0 <= offset - 1
    && offset - 1 < node.childNodes.length
    && isHtmlElement(node.childNodes[offset - 1], ["br", "hr", "img"]))) {
      // "Call collapse(node, offset) on the context object's Selection."
      getSelection().collapse(node, offset);
      getActiveRange().setEnd(node, offset);

      // "Call extend(node, offset − 1) on the context object's
      // Selection."
      getSelection().extend(node, offset - 1);
      getActiveRange().setStart(node, offset - 1);

      // "Delete the selection."
      deleteSelection();

      // "Return true."
      return true;
    }

    // "If node is an inline node, return true."
    if (isInlineNode(node)) {
      return true;
    }

    // "If node is an li or dt or dd and is the first child of its parent,
    // and offset is zero:"
    if (isHtmlElement(node, ["li", "dt", "dd"])
    && node == node.parentNode.firstChild
    && offset == 0) {
      // "Let items be a list of all lis that are ancestors of node."
      //
      // Remember, must be in tree order.
      var items = [];
      for (var ancestor = node.parentNode; ancestor; ancestor = ancestor.parentNode) {
        if (isHtmlElement(ancestor, "li")) {
          items.unshift(ancestor);
        }
      }

      // "Normalize sublists of each item in items."
      for (var i = 0; i < items.length; i++) {
        normalizeSublists(items[i]);
      }

      // "Record the values of the one-node list consisting of node, and
      // let values be the result."
      var values = recordValues([node]);

      // "Split the parent of the one-node list consisting of node."
      splitParent([node]);

      // "Restore the values from values."
      restoreValues(values);

      // "If node is a dd or dt, and it is not an allowed child of any of
      // its ancestors in the same editing host, set the tag name of node
      // to the default single-line container name and let node be the
      // result."
      if (isHtmlElement(node, ["dd", "dt"])
      && getAncestors(node).every(function(ancestor) {
        return !inSameEditingHost(node, ancestor)
          || !isAllowedChild(node, ancestor)
      })) {
        node = setTagName(node, defaultSingleLineContainerName);
      }

      // "Fix disallowed ancestors of node."
      fixDisallowedAncestors(node);

      // "Return true."
      return true;
    }

    // "Let start node equal node and let start offset equal offset."
    var startNode = node;
    var startOffset = offset;

    // "Repeat the following steps:"
    while (true) {
      // "If start offset is zero, set start offset to the index of start
      // node and then set start node to its parent."
      if (startOffset == 0) {
        startOffset = getNodeIndex(startNode);
        startNode = startNode.parentNode;

      // "Otherwise, if start node has an editable invisible child with
      // index start offset minus one, remove it from start node and
      // subtract one from start offset."
      } else if (0 <= startOffset - 1
      && startOffset - 1 < startNode.childNodes.length
      && isEditable(startNode.childNodes[startOffset - 1])
      && isInvisible(startNode.childNodes[startOffset - 1])) {
        startNode.removeChild(startNode.childNodes[startOffset - 1]);
        startOffset--;

      // "Otherwise, break from this loop."
      } else {
        break;
      }
    }

    // "If offset is zero, and node has an editable ancestor container in
    // the same editing host that's an indentation element:"
    if (offset == 0
    && getAncestors(node).concat(node).filter(function(ancestor) {
      return isEditable(ancestor)
        && inSameEditingHost(ancestor, node)
        && isIndentationElement(ancestor);
    }).length) {
      // "Block-extend the range whose start and end are both (node, 0),
      // and let new range be the result."
      var newRange = document.createRange();
      newRange.setStart(node, 0);
      newRange = blockExtend(newRange);

      // "Let node list be a list of nodes, initially empty."
      //
      // "For each node current node contained in new range, append
      // current node to node list if the last member of node list (if
      // any) is not an ancestor of current node, and current node is
      // editable but has no editable descendants."
      var nodeList = getContainedNodes(newRange, function(currentNode) {
        return isEditable(currentNode)
          && !hasEditableDescendants(currentNode);
      });

      // "Outdent each node in node list."
      for (var i = 0; i < nodeList.length; i++) {
        outdentNode(nodeList[i]);
      }

      // "Return true."
      return true;
    }

    // "If the child of start node with index start offset is a table,
    // return true."
    if (isHtmlElement(startNode.childNodes[startOffset], "table")) {
      return true;
    }

    // "If start node has a child with index start offset − 1, and that
    // child is a table:"
    if (0 <= startOffset - 1
    && startOffset - 1 < startNode.childNodes.length
    && isHtmlElement(startNode.childNodes[startOffset - 1], "table")) {
      // "Call collapse(start node, start offset − 1) on the context
      // object's Selection."
      getSelection().collapse(startNode, startOffset - 1);
      getActiveRange().setStart(startNode, startOffset - 1);

      // "Call extend(start node, start offset) on the context object's
      // Selection."
      getSelection().extend(startNode, startOffset);
      getActiveRange().setEnd(startNode, startOffset);

      // "Return true."
      return true;
    }

    // "If offset is zero; and either the child of start node with index
    // start offset minus one is an hr, or the child is a br whose
    // previousSibling is either a br or not an inline node:"
    if (offset == 0
    && (isHtmlElement(startNode.childNodes[startOffset - 1], "hr")
      || (
        isHtmlElement(startNode.childNodes[startOffset - 1], "br")
        && (
          isHtmlElement(startNode.childNodes[startOffset - 1].previousSibling, "br")
          || !isInlineNode(startNode.childNodes[startOffset - 1].previousSibling)
        )
      )
    )) {
      // "Call collapse(start node, start offset − 1) on the context
      // object's Selection."
      getSelection().collapse(startNode, startOffset - 1);
      getActiveRange().setStart(startNode, startOffset - 1);

      // "Call extend(start node, start offset) on the context object's
      // Selection."
      getSelection().extend(startNode, startOffset);
      getActiveRange().setEnd(startNode, startOffset);

      // "Delete the selection."
      deleteSelection();

      // "Call collapse(node, offset) on the Selection."
      getSelection().collapse(node, offset);
      getActiveRange().setStart(node, offset);
      getActiveRange().collapse(true);

      // "Return true."
      return true;
    }

    // "If the child of start node with index start offset is an li or dt
    // or dd, and that child's firstChild is an inline node, and start
    // offset is not zero:"
    if (isHtmlElement(startNode.childNodes[startOffset], ["li", "dt", "dd"])
    && isInlineNode(startNode.childNodes[startOffset].firstChild)
    && startOffset != 0) {
      // "Let previous item be the child of start node with index start
      // offset minus one."
      var previousItem = startNode.childNodes[startOffset - 1];

      // "If previous item's lastChild is an inline node other than a br,
      // call createElement("br") on the context object and append the
      // result as the last child of previous item."
      if (isInlineNode(previousItem.lastChild)
      && !isHtmlElement(previousItem.lastChild, "br")) {
        previousItem.appendChild(document.createElement("br"));
      }

      // "If previous item's lastChild is an inline node, call
      // createElement("br") on the context object and append the result
      // as the last child of previous item."
      if (isInlineNode(previousItem.lastChild)) {
        previousItem.appendChild(document.createElement("br"));
      }
    }

    // "If start node's child with index start offset is an li or dt or dd,
    // and that child's previousSibling is also an li or dt or dd:"
    if (isHtmlElement(startNode.childNodes[startOffset], ["li", "dt", "dd"])
    && isHtmlElement(startNode.childNodes[startOffset].previousSibling, ["li", "dt", "dd"])) {
      // "Call cloneRange() on the active range, and let original range
      // be the result."
      //
      // We need to add it to extraRanges so it will actually get updated
      // when moving preserving ranges.
      var originalRange = getActiveRange().cloneRange();
      extraRanges.push(originalRange);

      // "Set start node to its child with index start offset − 1."
      startNode = startNode.childNodes[startOffset - 1];

      // "Set start offset to start node's length."
      startOffset = getNodeLength(startNode);

      // "Set node to start node's nextSibling."
      node = startNode.nextSibling;

      // "Call collapse(start node, start offset) on the context object's
      // Selection."
      getSelection().collapse(startNode, startOffset);
      getActiveRange().setStart(startNode, startOffset);

      // "Call extend(node, 0) on the context object's Selection."
      getSelection().extend(node, 0);
      getActiveRange().setEnd(node, 0);

      // "Delete the selection."
      deleteSelection();

      // "Call removeAllRanges() on the context object's Selection."
      getSelection().removeAllRanges();

      // "Call addRange(original range) on the context object's
      // Selection."
      getSelection().addRange(originalRange);
      getActiveRange().setStart(originalRange.startContainer, originalRange.startOffset);
      getActiveRange().setEnd(originalRange.endContainer, originalRange.endOffset);

      // "Return true."
      extraRanges.pop();
      return true;
    }

    // "While start node has a child with index start offset minus one:"
    while (0 <= startOffset - 1
    && startOffset - 1 < startNode.childNodes.length) {
      // "If start node's child with index start offset minus one is
      // editable and invisible, remove it from start node, then subtract
      // one from start offset."
      if (isEditable(startNode.childNodes[startOffset - 1])
      && isInvisible(startNode.childNodes[startOffset - 1])) {
        startNode.removeChild(startNode.childNodes[startOffset - 1]);
        startOffset--;

      // "Otherwise, set start node to its child with index start offset
      // minus one, then set start offset to the length of start node."
      } else {
        startNode = startNode.childNodes[startOffset - 1];
        startOffset = getNodeLength(startNode);
      }
    }

    // "Call collapse(start node, start offset) on the context object's
    // Selection."
    getSelection().collapse(startNode, startOffset);
    getActiveRange().setStart(startNode, startOffset);

    // "Call extend(node, offset) on the context object's Selection."
    getSelection().extend(node, offset);
    getActiveRange().setEnd(node, offset);

    // "Delete the selection, with direction "backward"."
    deleteSelection({direction: "backward"});

    // "Return true."
    return true;
  }
};

//@}
///// The formatBlock command /////
//@{
// "A formattable block name is "address", "dd", "div", "dt", "h1", "h2", "h3",
// "h4", "h5", "h6", "p", or "pre"."
var formattableBlockNames = ["address", "dd", "div", "dt", "h1", "h2", "h3",
  "h4", "h5", "h6", "p", "pre"];

commands.formatblock = {
  preservesOverrides: true,
  action: function(value) {
    // "If value begins with a "<" character and ends with a ">" character,
    // remove the first and last characters from it."
    if (/^<.*>$/.test(value)) {
      value = value.slice(1, -1);
    }

    // "Let value be converted to ASCII lowercase."
    value = value.toLowerCase();

    // "If value is not a formattable block name, return false."
    if (formattableBlockNames.indexOf(value) == -1) {
      return false;
    }

    // "Block-extend the active range, and let new range be the result."
    var newRange = blockExtend(getActiveRange());

    // "Let node list be an empty list of nodes."
    //
    // "For each node node contained in new range, append node to node list
    // if it is editable, the last member of original node list (if any) is
    // not an ancestor of node, node is either a non-list single-line
    // container or an allowed child of "p" or a dd or dt, and node is not
    // the ancestor of a prohibited paragraph child."
    var nodeList = getContainedNodes(newRange, function(node) {
      return isEditable(node)
        && (isNonListSingleLineContainer(node)
        || isAllowedChild(node, "p")
        || isHtmlElement(node, ["dd", "dt"]))
        && !getDescendants(node).some(isProhibitedParagraphChild);
    });

    // "Record the values of node list, and let values be the result."
    var values = recordValues(nodeList);

    // "For each node in node list, while node is the descendant of an
    // editable HTML element in the same editing host, whose local name is
    // a formattable block name, and which is not the ancestor of a
    // prohibited paragraph child, split the parent of the one-node list
    // consisting of node."
    for (var i = 0; i < nodeList.length; i++) {
      var node = nodeList[i];
      while (getAncestors(node).some(function(ancestor) {
        return isEditable(ancestor)
          && inSameEditingHost(ancestor, node)
          && isHtmlElement(ancestor, formattableBlockNames)
          && !getDescendants(ancestor).some(isProhibitedParagraphChild);
      })) {
        splitParent([node]);
      }
    }

    // "Restore the values from values."
    restoreValues(values);

    // "While node list is not empty:"
    while (nodeList.length) {
      var sublist;

      // "If the first member of node list is a single-line
      // container:"
      if (isSingleLineContainer(nodeList[0])) {
        // "Let sublist be the children of the first member of node
        // list."
        sublist = [].slice.call(nodeList[0].childNodes);

        // "Record the values of sublist, and let values be the
        // result."
        var values = recordValues(sublist);

        // "Remove the first member of node list from its parent,
        // preserving its descendants."
        removePreservingDescendants(nodeList[0]);

        // "Restore the values from values."
        restoreValues(values);

        // "Remove the first member from node list."
        nodeList.shift();

      // "Otherwise:"
      } else {
        // "Let sublist be an empty list of nodes."
        sublist = [];

        // "Remove the first member of node list and append it to
        // sublist."
        sublist.push(nodeList.shift());

        // "While node list is not empty, and the first member of
        // node list is the nextSibling of the last member of
        // sublist, and the first member of node list is not a
        // single-line container, and the last member of sublist is
        // not a br, remove the first member of node list and
        // append it to sublist."
        while (nodeList.length
        && nodeList[0] == sublist[sublist.length - 1].nextSibling
        && !isSingleLineContainer(nodeList[0])
        && !isHtmlElement(sublist[sublist.length - 1], "BR")) {
          sublist.push(nodeList.shift());
        }
      }

      // "Wrap sublist. If value is "div" or "p", sibling criteria
      // returns false; otherwise it returns true for an HTML element
      // with local name value and no attributes, and false otherwise.
      // New parent instructions return the result of running
      // createElement(value) on the context object. Then fix disallowed
      // ancestors of the result."
      fixDisallowedAncestors(wrap(sublist,
        ["div", "p"].indexOf(value) == - 1
          ? function(node) { return isHtmlElement(node, value) && !node.attributes.length }
          : function() { return false },
        function() { return document.createElement(value) }));
    }

    // "Return true."
    return true;
  }, indeterm: function() {
    // "If the active range is null, return false."
    if (!getActiveRange()) {
      return false;
    }

    // "Block-extend the active range, and let new range be the result."
    var newRange = blockExtend(getActiveRange());

    // "Let node list be all visible editable nodes that are contained in
    // new range and have no children."
    var nodeList = getAllContainedNodes(newRange, function(node) {
      return isVisible(node)
        && isEditable(node)
        && !node.hasChildNodes();
    });

    // "If node list is empty, return false."
    if (!nodeList.length) {
      return false;
    }

    // "Let type be null."
    var type = null;

    // "For each node in node list:"
    for (var i = 0; i < nodeList.length; i++) {
      var node = nodeList[i];

      // "While node's parent is editable and in the same editing host as
      // node, and node is not an HTML element whose local name is a
      // formattable block name, set node to its parent."
      while (isEditable(node.parentNode)
      && inSameEditingHost(node, node.parentNode)
      && !isHtmlElement(node, formattableBlockNames)) {
        node = node.parentNode;
      }

      // "Let current type be the empty string."
      var currentType = "";

      // "If node is an editable HTML element whose local name is a
      // formattable block name, and node is not the ancestor of a
      // prohibited paragraph child, set current type to node's local
      // name."
      if (isEditable(node)
      && isHtmlElement(node, formattableBlockNames)
      && !getDescendants(node).some(isProhibitedParagraphChild)) {
        currentType = node.tagName;
      }

      // "If type is null, set type to current type."
      if (type === null) {
        type = currentType;

      // "Otherwise, if type does not equal current type, return true."
      } else if (type != currentType) {
        return true;
      }
    }

    // "Return false."
    return false;
  }, value: function() {
    // "If the active range is null, return the empty string."
    if (!getActiveRange()) {
      return "";
    }

    // "Block-extend the active range, and let new range be the result."
    var newRange = blockExtend(getActiveRange());

    // "Let node be the first visible editable node that is contained in
    // new range and has no children. If there is no such node, return the
    // empty string."
    var nodes = getAllContainedNodes(newRange, function(node) {
      return isVisible(node)
        && isEditable(node)
        && !node.hasChildNodes();
    });
    if (!nodes.length) {
      return "";
    }
    var node = nodes[0];

    // "While node's parent is editable and in the same editing host as
    // node, and node is not an HTML element whose local name is a
    // formattable block name, set node to its parent."
    while (isEditable(node.parentNode)
    && inSameEditingHost(node, node.parentNode)
    && !isHtmlElement(node, formattableBlockNames)) {
      node = node.parentNode;
    }

    // "If node is an editable HTML element whose local name is a
    // formattable block name, and node is not the ancestor of a prohibited
    // paragraph child, return node's local name, converted to ASCII
    // lowercase."
    if (isEditable(node)
    && isHtmlElement(node, formattableBlockNames)
    && !getDescendants(node).some(isProhibitedParagraphChild)) {
      return node.tagName.toLowerCase();
    }

    // "Return the empty string."
    return "";
  }
};

//@}
///// The forwardDelete command /////
//@{
commands.forwarddelete = {
  preservesOverrides: true,
  action: function() {
    // "If the active range is not collapsed, delete the selection and
    // return true."
    if (!getActiveRange().collapsed) {
      deleteSelection();
      return true;
    }

    // "Canonicalize whitespace at the active range's start."
    canonicalizeWhitespace(getActiveRange().startContainer, getActiveRange().startOffset);

    // "Let node and offset be the active range's start node and offset."
    var node = getActiveRange().startContainer;
    var offset = getActiveRange().startOffset;

    // "Repeat the following steps:"
    while (true) {
      // "If offset is the length of node and node's nextSibling is an
      // editable invisible node, remove node's nextSibling from its
      // parent."
      if (offset == getNodeLength(node)
      && isEditable(node.nextSibling)
      && isInvisible(node.nextSibling)) {
        node.parentNode.removeChild(node.nextSibling);

      // "Otherwise, if node has a child with index offset and that child
      // is an editable invisible node, remove that child from node."
      } else if (offset < node.childNodes.length
      && isEditable(node.childNodes[offset])
      && isInvisible(node.childNodes[offset])) {
        node.removeChild(node.childNodes[offset]);

      // "Otherwise, if offset is the length of node and node is an
      // inline node, or if node is invisible, set offset to one plus the
      // index of node, then set node to its parent."
      } else if ((offset == getNodeLength(node)
      && isInlineNode(node))
      || isInvisible(node)) {
        offset = 1 + getNodeIndex(node);
        node = node.parentNode;

      // "Otherwise, if node has a child with index offset and that child
      // is neither a block node nor a br nor an img nor a collapsed
      // block prop, set node to that child, then set offset to zero."
      } else if (offset < node.childNodes.length
      && !isBlockNode(node.childNodes[offset])
      && !isHtmlElement(node.childNodes[offset], ["br", "img"])
      && !isCollapsedBlockProp(node.childNodes[offset])) {
        node = node.childNodes[offset];
        offset = 0;

      // "Otherwise, break from this loop."
      } else {
        break;
      }
    }

    // "If node is a Text node and offset is not node's length:"
    if (node.nodeType == Node.TEXT_NODE
    && offset != getNodeLength(node)) {
      // "Let end offset be offset plus one."
      var endOffset = offset + 1;

      // "While end offset is not node's length and the end offsetth
      // element of node's data has general category M when interpreted
      // as a Unicode code point, add one to end offset."
      //
      // TODO: Not even going to try handling anything beyond the most
      // basic combining marks, since I couldn't find a good list.  I
      // special-case a few Hebrew diacritics too to test basic coverage
      // of non-Latin stuff.
      while (endOffset != node.length
      && /^[\u0300-\u036f\u0591-\u05bd\u05c1\u05c2]$/.test(node.data[endOffset])) {
        endOffset++;
      }

      // "Call collapse(node, offset) on the context object's Selection."
      getSelection().collapse(node, offset);
      getActiveRange().setStart(node, offset);

      // "Call extend(node, end offset) on the context object's
      // Selection."
      getSelection().extend(node, endOffset);
      getActiveRange().setEnd(node, endOffset);

      // "Delete the selection."
      deleteSelection();

      // "Return true."
      return true;
    }

    // "If node is an inline node, return true."
    if (isInlineNode(node)) {
      return true;
    }

    // "If node has a child with index offset and that child is a br or hr
    // or img, but is not a collapsed block prop:"
    if (offset < node.childNodes.length
    && isHtmlElement(node.childNodes[offset], ["br", "hr", "img"])
    && !isCollapsedBlockProp(node.childNodes[offset])) {
      // "Call collapse(node, offset) on the context object's Selection."
      getSelection().collapse(node, offset);
      getActiveRange().setStart(node, offset);

      // "Call extend(node, offset + 1) on the context object's
      // Selection."
      getSelection().extend(node, offset + 1);
      getActiveRange().setEnd(node, offset + 1);

      // "Delete the selection."
      deleteSelection();

      // "Return true."
      return true;
    }

    // "Let end node equal node and let end offset equal offset."
    var endNode = node;
    var endOffset = offset;

    // "If end node has a child with index end offset, and that child is a
    // collapsed block prop, add one to end offset."
    if (endOffset < endNode.childNodes.length
    && isCollapsedBlockProp(endNode.childNodes[endOffset])) {
      endOffset++;
    }

    // "Repeat the following steps:"
    while (true) {
      // "If end offset is the length of end node, set end offset to one
      // plus the index of end node and then set end node to its parent."
      if (endOffset == getNodeLength(endNode)) {
        endOffset = 1 + getNodeIndex(endNode);
        endNode = endNode.parentNode;

      // "Otherwise, if end node has a an editable invisible child with
      // index end offset, remove it from end node."
      } else if (endOffset < endNode.childNodes.length
      && isEditable(endNode.childNodes[endOffset])
      && isInvisible(endNode.childNodes[endOffset])) {
        endNode.removeChild(endNode.childNodes[endOffset]);

      // "Otherwise, break from this loop."
      } else {
        break;
      }
    }

    // "If the child of end node with index end offset minus one is a
    // table, return true."
    if (isHtmlElement(endNode.childNodes[endOffset - 1], "table")) {
      return true;
    }

    // "If the child of end node with index end offset is a table:"
    if (isHtmlElement(endNode.childNodes[endOffset], "table")) {
      // "Call collapse(end node, end offset) on the context object's
      // Selection."
      getSelection().collapse(endNode, endOffset);
      getActiveRange().setStart(endNode, endOffset);

      // "Call extend(end node, end offset + 1) on the context object's
      // Selection."
      getSelection().extend(endNode, endOffset + 1);
      getActiveRange().setEnd(endNode, endOffset + 1);

      // "Return true."
      return true;
    }

    // "If offset is the length of node, and the child of end node with
    // index end offset is an hr or br:"
    if (offset == getNodeLength(node)
    && isHtmlElement(endNode.childNodes[endOffset], ["br", "hr"])) {
      // "Call collapse(end node, end offset) on the context object's
      // Selection."
      getSelection().collapse(endNode, endOffset);
      getActiveRange().setStart(endNode, endOffset);

      // "Call extend(end node, end offset + 1) on the context object's
      // Selection."
      getSelection().extend(endNode, endOffset + 1);
      getActiveRange().setEnd(endNode, endOffset + 1);

      // "Delete the selection."
      deleteSelection();

      // "Call collapse(node, offset) on the Selection."
      getSelection().collapse(node, offset);
      getActiveRange().setStart(node, offset);
      getActiveRange().collapse(true);

      // "Return true."
      return true;
    }

    // "While end node has a child with index end offset:"
    while (endOffset < endNode.childNodes.length) {
      // "If end node's child with index end offset is editable and
      // invisible, remove it from end node."
      if (isEditable(endNode.childNodes[endOffset])
      && isInvisible(endNode.childNodes[endOffset])) {
        endNode.removeChild(endNode.childNodes[endOffset]);

      // "Otherwise, set end node to its child with index end offset and
      // set end offset to zero."
      } else {
        endNode = endNode.childNodes[endOffset];
        endOffset = 0;
      }
    }

    // "Call collapse(node, offset) on the context object's Selection."
    getSelection().collapse(node, offset);
    getActiveRange().setStart(node, offset);

    // "Call extend(end node, end offset) on the context object's
    // Selection."
    getSelection().extend(endNode, endOffset);
    getActiveRange().setEnd(endNode, endOffset);

    // "Delete the selection."
    deleteSelection();

    // "Return true."
    return true;
  }
};

//@}
///// The indent command /////
//@{
commands.indent = {
  preservesOverrides: true,
  action: function() {
    // "Let items be a list of all lis that are ancestor containers of the
    // active range's start and/or end node."
    //
    // Has to be in tree order, remember!
    var items = [];
    for (var node = getActiveRange().endContainer; node != getActiveRange().commonAncestorContainer; node = node.parentNode) {
      if (isHtmlElement(node, "LI")) {
        items.unshift(node);
      }
    }
    for (var node = getActiveRange().startContainer; node != getActiveRange().commonAncestorContainer; node = node.parentNode) {
      if (isHtmlElement(node, "LI")) {
        items.unshift(node);
      }
    }
    for (var node = getActiveRange().commonAncestorContainer; node; node = node.parentNode) {
      if (isHtmlElement(node, "LI")) {
        items.unshift(node);
      }
    }

    // "For each item in items, normalize sublists of item."
    for (var i = 0; i < items.length; i++) {
      normalizeSublists(items[i]);
    }

    // "Block-extend the active range, and let new range be the result."
    var newRange = blockExtend(getActiveRange());

    // "Let node list be a list of nodes, initially empty."
    var nodeList = [];

    // "For each node node contained in new range, if node is editable and
    // is an allowed child of "div" or "ol" and if the last member of node
    // list (if any) is not an ancestor of node, append node to node list."
    nodeList = getContainedNodes(newRange, function(node) {
      return isEditable(node)
        && (isAllowedChild(node, "div")
        || isAllowedChild(node, "ol"));
    });

    // "If the first visible member of node list is an li whose parent is
    // an ol or ul:"
    if (isHtmlElement(nodeList.filter(isVisible)[0], "li")
    && isHtmlElement(nodeList.filter(isVisible)[0].parentNode, ["ol", "ul"])) {
      // "Let sibling be node list's first visible member's
      // previousSibling."
      var sibling = nodeList.filter(isVisible)[0].previousSibling;

      // "While sibling is invisible, set sibling to its
      // previousSibling."
      while (isInvisible(sibling)) {
        sibling = sibling.previousSibling;
      }

      // "If sibling is an li, normalize sublists of sibling."
      if (isHtmlElement(sibling, "li")) {
        normalizeSublists(sibling);
      }
    }

    // "While node list is not empty:"
    while (nodeList.length) {
      // "Let sublist be a list of nodes, initially empty."
      var sublist = [];

      // "Remove the first member of node list and append it to sublist."
      sublist.push(nodeList.shift());

      // "While the first member of node list is the nextSibling of the
      // last member of sublist, remove the first member of node list and
      // append it to sublist."
      while (nodeList.length
      && nodeList[0] == sublist[sublist.length - 1].nextSibling) {
        sublist.push(nodeList.shift());
      }

      // "Indent sublist."
      indentNodes(sublist);
    }

    // "Return true."
    return true;
  }
};

//@}
///// The insertHorizontalRule command /////
//@{
commands.inserthorizontalrule = {
  preservesOverrides: true,
  action: function() {
    // "Let start node, start offset, end node, and end offset be the
    // active range's start and end nodes and offsets."
    var startNode = getActiveRange().startContainer;
    var startOffset = getActiveRange().startOffset;
    var endNode = getActiveRange().endContainer;
    var endOffset = getActiveRange().endOffset;

    // "While start offset is 0 and start node's parent is not null, set
    // start offset to start node's index, then set start node to its
    // parent."
    while (startOffset == 0
    && startNode.parentNode) {
      startOffset = getNodeIndex(startNode);
      startNode = startNode.parentNode;
    }

    // "While end offset is end node's length, and end node's parent is not
    // null, set end offset to one plus end node's index, then set end node
    // to its parent."
    while (endOffset == getNodeLength(endNode)
    && endNode.parentNode) {
      endOffset = 1 + getNodeIndex(endNode);
      endNode = endNode.parentNode;
    }

    // "Call collapse(start node, start offset) on the context object's
    // Selection."
    getSelection().collapse(startNode, startOffset);
    getActiveRange().setStart(startNode, startOffset);

    // "Call extend(end node, end offset) on the context object's
    // Selection."
    getSelection().extend(endNode, endOffset);
    getActiveRange().setEnd(endNode, endOffset);

    // "Delete the selection, with block merging false."
    deleteSelection({blockMerging: false});

    // "If the active range's start node is neither editable nor an editing
    // host, return true."
    if (!isEditable(getActiveRange().startContainer)
    && !isEditingHost(getActiveRange().startContainer)) {
      return true;
    }

    // "If the active range's start node is a Text node and its start
    // offset is zero, call collapse() on the context object's Selection,
    // with first argument the active range's start node's parent and
    // second argument the active range's start node's index."
    if (getActiveRange().startContainer.nodeType == Node.TEXT_NODE
    && getActiveRange().startOffset == 0) {
      var newNode = getActiveRange().startContainer.parentNode;
      var newOffset = getNodeIndex(getActiveRange().startContainer);
      getSelection().collapse(newNode, newOffset);
      getActiveRange().setStart(newNode, newOffset);
      getActiveRange().collapse(true);
    }

    // "If the active range's start node is a Text node and its start
    // offset is the length of its start node, call collapse() on the
    // context object's Selection, with first argument the active range's
    // start node's parent, and the second argument one plus the active
    // range's start node's index."
    if (getActiveRange().startContainer.nodeType == Node.TEXT_NODE
    && getActiveRange().startOffset == getNodeLength(getActiveRange().startContainer)) {
      var newNode = getActiveRange().startContainer.parentNode;
      var newOffset = 1 + getNodeIndex(getActiveRange().startContainer);
      getSelection().collapse(newNode, newOffset);
      getActiveRange().setStart(newNode, newOffset);
      getActiveRange().collapse(true);
    }

    // "Let hr be the result of calling createElement("hr") on the
    // context object."
    var hr = document.createElement("hr");

    // "Run insertNode(hr) on the active range."
    getActiveRange().insertNode(hr);

    // "Fix disallowed ancestors of hr."
    fixDisallowedAncestors(hr);

    // "Run collapse() on the context object's Selection, with first
    // argument hr's parent and the second argument equal to one plus hr's
    // index."
    getSelection().collapse(hr.parentNode, 1 + getNodeIndex(hr));
    getActiveRange().setStart(hr.parentNode, 1 + getNodeIndex(hr));
    getActiveRange().collapse(true);

    // "Return true."
    return true;
  }
};

//@}
///// The insertHTML command /////
//@{
commands.inserthtml = {
  preservesOverrides: true,
  action: function(value) {
    // "Delete the selection."
    deleteSelection();

    // "If the active range's start node is neither editable nor an editing
    // host, return true."
    if (!isEditable(getActiveRange().startContainer)
    && !isEditingHost(getActiveRange().startContainer)) {
      return true;
    }

    // "Let frag be the result of calling createContextualFragment(value)
    // on the active range."
    var frag = getActiveRange().createContextualFragment(value);

    // "Let last child be the lastChild of frag."
    var lastChild = frag.lastChild;

    // "If last child is null, return true."
    if (!lastChild) {
      return true;
    }

    // "Let descendants be all descendants of frag."
    var descendants = getDescendants(frag);

    // "If the active range's start node is a block node:"
    if (isBlockNode(getActiveRange().startContainer)) {
      // "Let collapsed block props be all editable collapsed block prop
      // children of the active range's start node that have index
      // greater than or equal to the active range's start offset."
      //
      // "For each node in collapsed block props, remove node from its
      // parent."
      [].filter.call(getActiveRange().startContainer.childNodes, function(node) {
        return isEditable(node)
          && isCollapsedBlockProp(node)
          && getNodeIndex(node) >= getActiveRange().startOffset;
      }).forEach(function(node) {
        node.parentNode.removeChild(node);
      });
    }

    // "Call insertNode(frag) on the active range."
    getActiveRange().insertNode(frag);

    // "If the active range's start node is a block node with no visible
    // children, call createElement("br") on the context object and append
    // the result as the last child of the active range's start node."
    if (isBlockNode(getActiveRange().startContainer)
    && ![].some.call(getActiveRange().startContainer.childNodes, isVisible)) {
      getActiveRange().startContainer.appendChild(document.createElement("br"));
    }

    // "Call collapse() on the context object's Selection, with last
    // child's parent as the first argument and one plus its index as the
    // second."
    getActiveRange().setStart(lastChild.parentNode, 1 + getNodeIndex(lastChild));
    getActiveRange().setEnd(lastChild.parentNode, 1 + getNodeIndex(lastChild));

    // "Fix disallowed ancestors of each member of descendants."
    for (var i = 0; i < descendants.length; i++) {
      fixDisallowedAncestors(descendants[i]);
    }

    // "Return true."
    return true;
  }
};

//@}
///// The insertImage command /////
//@{
commands.insertimage = {
  preservesOverrides: true,
  action: function(value) {
    // "If value is the empty string, return false."
    if (value === "") {
      return false;
    }

    // "Delete the selection, with strip wrappers false."
    deleteSelection({stripWrappers: false});

    // "Let range be the active range."
    var range = getActiveRange();

    // "If the active range's start node is neither editable nor an editing
    // host, return true."
    if (!isEditable(getActiveRange().startContainer)
    && !isEditingHost(getActiveRange().startContainer)) {
      return true;
    }

    // "If range's start node is a block node whose sole child is a br, and
    // its start offset is 0, remove its start node's child from it."
    if (isBlockNode(range.startContainer)
    && range.startContainer.childNodes.length == 1
    && isHtmlElement(range.startContainer.firstChild, "br")
    && range.startOffset == 0) {
      range.startContainer.removeChild(range.startContainer.firstChild);
    }

    // "Let img be the result of calling createElement("img") on the
    // context object."
    var img = document.createElement("img");

    // "Run setAttribute("src", value) on img."
    img.setAttribute("src", value);

    // "Run insertNode(img) on the range."
    range.insertNode(img);

    // "Run collapse() on the Selection, with first argument equal to the
    // parent of img and the second argument equal to one plus the index of
    // img."
    //
    // Not everyone actually supports collapse(), so we do it manually
    // instead.  Also, we need to modify the actual range we're given as
    // well, for the sake of autoimplementation.html's range-filling-in.
    range.setStart(img.parentNode, 1 + getNodeIndex(img));
    range.setEnd(img.parentNode, 1 + getNodeIndex(img));
    getSelection().removeAllRanges();
    getSelection().addRange(range);

    // IE adds width and height attributes for some reason, so remove those
    // to actually do what the spec says.
    img.removeAttribute("width");
    img.removeAttribute("height");

    // "Return true."
    return true;
  }
};

//@}
///// The insertLineBreak command /////
//@{
commands.insertlinebreak = {
  preservesOverrides: true,
  action: function(value) {
    // "Delete the selection, with strip wrappers false."
    deleteSelection({stripWrappers: false});

    // "If the active range's start node is neither editable nor an editing
    // host, return true."
    if (!isEditable(getActiveRange().startContainer)
    && !isEditingHost(getActiveRange().startContainer)) {
      return true;
    }

    // "If the active range's start node is an Element, and "br" is not an
    // allowed child of it, return true."
    if (getActiveRange().startContainer.nodeType == Node.ELEMENT_NODE
    && !isAllowedChild("br", getActiveRange().startContainer)) {
      return true;
    }

    // "If the active range's start node is not an Element, and "br" is not
    // an allowed child of the active range's start node's parent, return
    // true."
    if (getActiveRange().startContainer.nodeType != Node.ELEMENT_NODE
    && !isAllowedChild("br", getActiveRange().startContainer.parentNode)) {
      return true;
    }

    // "If the active range's start node is a Text node and its start
    // offset is zero, call collapse() on the context object's Selection,
    // with first argument equal to the active range's start node's parent
    // and second argument equal to the active range's start node's index."
    if (getActiveRange().startContainer.nodeType == Node.TEXT_NODE
    && getActiveRange().startOffset == 0) {
      var newNode = getActiveRange().startContainer.parentNode;
      var newOffset = getNodeIndex(getActiveRange().startContainer);
      getSelection().collapse(newNode, newOffset);
      getActiveRange().setStart(newNode, newOffset);
      getActiveRange().setEnd(newNode, newOffset);
    }

    // "If the active range's start node is a Text node and its start
    // offset is the length of its start node, call collapse() on the
    // context object's Selection, with first argument equal to the active
    // range's start node's parent and second argument equal to one plus
    // the active range's start node's index."
    if (getActiveRange().startContainer.nodeType == Node.TEXT_NODE
    && getActiveRange().startOffset == getNodeLength(getActiveRange().startContainer)) {
      var newNode = getActiveRange().startContainer.parentNode;
      var newOffset = 1 + getNodeIndex(getActiveRange().startContainer);
      getSelection().collapse(newNode, newOffset);
      getActiveRange().setStart(newNode, newOffset);
      getActiveRange().setEnd(newNode, newOffset);
    }

    // "Let br be the result of calling createElement("br") on the context
    // object."
    var br = document.createElement("br");

    // "Call insertNode(br) on the active range."
    getActiveRange().insertNode(br);

    // "Call collapse() on the context object's Selection, with br's parent
    // as the first argument and one plus br's index as the second
    // argument."
    getSelection().collapse(br.parentNode, 1 + getNodeIndex(br));
    getActiveRange().setStart(br.parentNode, 1 + getNodeIndex(br));
    getActiveRange().setEnd(br.parentNode, 1 + getNodeIndex(br));

    // "If br is a collapsed line break, call createElement("br") on the
    // context object and let extra br be the result, then call
    // insertNode(extra br) on the active range."
    if (isCollapsedLineBreak(br)) {
      getActiveRange().insertNode(document.createElement("br"));

      // Compensate for nonstandard implementations of insertNode
      getSelection().collapse(br.parentNode, 1 + getNodeIndex(br));
      getActiveRange().setStart(br.parentNode, 1 + getNodeIndex(br));
      getActiveRange().setEnd(br.parentNode, 1 + getNodeIndex(br));
    }

    // "Return true."
    return true;
  }
};

//@}
///// The insertOrderedList command /////
//@{
commands.insertorderedlist = {
  preservesOverrides: true,
  // "Toggle lists with tag name "ol", then return true."
  action: function() { toggleLists("ol"); return true },
  // "True if the selection's list state is "mixed" or "mixed ol", false
  // otherwise."
  indeterm: function() { return /^mixed( ol)?$/.test(getSelectionListState()) },
  // "True if the selection's list state is "ol", false otherwise."
  state: function() { return getSelectionListState() == "ol" },
};

//@}
///// The insertParagraph command /////
//@{
commands.insertparagraph = {
  preservesOverrides: true,
  action: function() {
    // "Delete the selection."
    deleteSelection();

    // "If the active range's start node is neither editable nor an editing
    // host, return true."
    if (!isEditable(getActiveRange().startContainer)
    && !isEditingHost(getActiveRange().startContainer)) {
      return true;
    }

    // "Let node and offset be the active range's start node and offset."
    var node = getActiveRange().startContainer;
    var offset = getActiveRange().startOffset;

    // "If node is a Text node, and offset is neither 0 nor the length of
    // node, call splitText(offset) on node."
    if (node.nodeType == Node.TEXT_NODE
    && offset != 0
    && offset != getNodeLength(node)) {
      node.splitText(offset);
    }

    // "If node is a Text node and offset is its length, set offset to one
    // plus the index of node, then set node to its parent."
    if (node.nodeType == Node.TEXT_NODE
    && offset == getNodeLength(node)) {
      offset = 1 + getNodeIndex(node);
      node = node.parentNode;
    }

    // "If node is a Text or Comment node, set offset to the index of node,
    // then set node to its parent."
    if (node.nodeType == Node.TEXT_NODE
    || node.nodeType == Node.COMMENT_NODE) {
      offset = getNodeIndex(node);
      node = node.parentNode;
    }

    // "Call collapse(node, offset) on the context object's Selection."
    getSelection().collapse(node, offset);
    getActiveRange().setStart(node, offset);
    getActiveRange().setEnd(node, offset);

    // "Let container equal node."
    var container = node;

    // "While container is not a single-line container, and container's
    // parent is editable and in the same editing host as node, set
    // container to its parent."
    while (!isSingleLineContainer(container)
    && isEditable(container.parentNode)
    && inSameEditingHost(node, container.parentNode)) {
      container = container.parentNode;
    }

    // "If container is an editable single-line container in the same
    // editing host as node, and its local name is "p" or "div":"
    if (isEditable(container)
    && isSingleLineContainer(container)
    && inSameEditingHost(node, container.parentNode)
    && (container.tagName == "P" || container.tagName == "DIV")) {
      // "Let outer container equal container."
      var outerContainer = container;

      // "While outer container is not a dd or dt or li, and outer
      // container's parent is editable, set outer container to its
      // parent."
      while (!isHtmlElement(outerContainer, ["dd", "dt", "li"])
      && isEditable(outerContainer.parentNode)) {
        outerContainer = outerContainer.parentNode;
      }

      // "If outer container is a dd or dt or li, set container to outer
      // container."
      if (isHtmlElement(outerContainer, ["dd", "dt", "li"])) {
        container = outerContainer;
      }
    }

    // "If container is not editable or not in the same editing host as
    // node or is not a single-line container:"
    if (!isEditable(container)
    || !inSameEditingHost(container, node)
    || !isSingleLineContainer(container)) {
      // "Let tag be the default single-line container name."
      var tag = defaultSingleLineContainerName;

      // "Block-extend the active range, and let new range be the
      // result."
      var newRange = blockExtend(getActiveRange());

      // "Let node list be a list of nodes, initially empty."
      //
      // "Append to node list the first node in tree order that is
      // contained in new range and is an allowed child of "p", if any."
      var nodeList = getContainedNodes(newRange, function(node) { return isAllowedChild(node, "p") })
        .slice(0, 1);

      // "If node list is empty:"
      if (!nodeList.length) {
        // "If tag is not an allowed child of the active range's start
        // node, return true."
        if (!isAllowedChild(tag, getActiveRange().startContainer)) {
          return true;
        }

        // "Set container to the result of calling createElement(tag)
        // on the context object."
        container = document.createElement(tag);

        // "Call insertNode(container) on the active range."
        getActiveRange().insertNode(container);

        // "Call createElement("br") on the context object, and append
        // the result as the last child of container."
        container.appendChild(document.createElement("br"));

        // "Call collapse(container, 0) on the context object's
        // Selection."
        getSelection().collapse(container, 0);
        getActiveRange().setStart(container, 0);
        getActiveRange().setEnd(container, 0);

        // "Return true."
        return true;
      }

      // "While the nextSibling of the last member of node list is not
      // null and is an allowed child of "p", append it to node list."
      while (nodeList[nodeList.length - 1].nextSibling
      && isAllowedChild(nodeList[nodeList.length - 1].nextSibling, "p")) {
        nodeList.push(nodeList[nodeList.length - 1].nextSibling);
      }

      // "Wrap node list, with sibling criteria returning false and new
      // parent instructions returning the result of calling
      // createElement(tag) on the context object. Set container to the
      // result."
      container = wrap(nodeList,
        function() { return false },
        function() { return document.createElement(tag) }
      );
    }

    // "If container's local name is "address", "listing", or "pre":"
    if (container.tagName == "ADDRESS"
    || container.tagName == "LISTING"
    || container.tagName == "PRE") {
      // "Let br be the result of calling createElement("br") on the
      // context object."
      var br = document.createElement("br");

      // "Call insertNode(br) on the active range."
      getActiveRange().insertNode(br);

      // "Call collapse(node, offset + 1) on the context object's
      // Selection."
      getSelection().collapse(node, offset + 1);
      getActiveRange().setStart(node, offset + 1);
      getActiveRange().setEnd(node, offset + 1);

      // "If br is the last descendant of container, let br be the result
      // of calling createElement("br") on the context object, then call
      // insertNode(br) on the active range."
      //
      // Work around browser bugs: some browsers select the
      // newly-inserted node, not per spec.
      if (!isDescendant(nextNode(br), container)) {
        getActiveRange().insertNode(document.createElement("br"));
        getSelection().collapse(node, offset + 1);
        getActiveRange().setEnd(node, offset + 1);
      }

      // "Return true."
      return true;
    }

    // "If container's local name is "li", "dt", or "dd"; and either it has
    // no children or it has a single child and that child is a br:"
    if (["LI", "DT", "DD"].indexOf(container.tagName) != -1
    && (!container.hasChildNodes()
    || (container.childNodes.length == 1
    && isHtmlElement(container.firstChild, "br")))) {
      // "Split the parent of the one-node list consisting of container."
      splitParent([container]);

      // "If container has no children, call createElement("br") on the
      // context object and append the result as the last child of
      // container."
      if (!container.hasChildNodes()) {
        container.appendChild(document.createElement("br"));
      }

      // "If container is a dd or dt, and it is not an allowed child of
      // any of its ancestors in the same editing host, set the tag name
      // of container to the default single-line container name and let
      // container be the result."
      if (isHtmlElement(container, ["dd", "dt"])
      && getAncestors(container).every(function(ancestor) {
        return !inSameEditingHost(container, ancestor)
          || !isAllowedChild(container, ancestor)
      })) {
        container = setTagName(container, defaultSingleLineContainerName);
      }

      // "Fix disallowed ancestors of container."
      fixDisallowedAncestors(container);

      // "Return true."
      return true;
    }

    // "Let new line range be a new range whose start is the same as
    // the active range's, and whose end is (container, length of
    // container)."
    var newLineRange = document.createRange();
    newLineRange.setStart(getActiveRange().startContainer, getActiveRange().startOffset);
    newLineRange.setEnd(container, getNodeLength(container));

    // "While new line range's start offset is zero and its start node is
    // not a prohibited paragraph child, set its start to (parent of start
    // node, index of start node)."
    while (newLineRange.startOffset == 0
    && !isProhibitedParagraphChild(newLineRange.startContainer)) {
      newLineRange.setStart(newLineRange.startContainer.parentNode, getNodeIndex(newLineRange.startContainer));
    }

    // "While new line range's start offset is the length of its start node
    // and its start node is not a prohibited paragraph child, set its
    // start to (parent of start node, 1 + index of start node)."
    while (newLineRange.startOffset == getNodeLength(newLineRange.startContainer)
    && !isProhibitedParagraphChild(newLineRange.startContainer)) {
      newLineRange.setStart(newLineRange.startContainer.parentNode, 1 + getNodeIndex(newLineRange.startContainer));
    }

    // "Let end of line be true if new line range contains either nothing
    // or a single br, and false otherwise."
    var containedInNewLineRange = getContainedNodes(newLineRange);
    var endOfLine = !containedInNewLineRange.length
      || (containedInNewLineRange.length == 1
      && isHtmlElement(containedInNewLineRange[0], "br"));

    // "If the local name of container is "h1", "h2", "h3", "h4", "h5", or
    // "h6", and end of line is true, let new container name be the default
    // single-line container name."
    var newContainerName;
    if (/^H[1-6]$/.test(container.tagName)
    && endOfLine) {
      newContainerName = defaultSingleLineContainerName;

    // "Otherwise, if the local name of container is "dt" and end of line
    // is true, let new container name be "dd"."
    } else if (container.tagName == "DT"
    && endOfLine) {
      newContainerName = "dd";

    // "Otherwise, if the local name of container is "dd" and end of line
    // is true, let new container name be "dt"."
    } else if (container.tagName == "DD"
    && endOfLine) {
      newContainerName = "dt";

    // "Otherwise, let new container name be the local name of container."
    } else {
      newContainerName = container.tagName.toLowerCase();
    }

    // "Let new container be the result of calling createElement(new
    // container name) on the context object."
    var newContainer = document.createElement(newContainerName);

    // "Copy all attributes of container to new container."
    for (var i = 0; i < container.attributes.length; i++) {
      newContainer.setAttributeNS(container.attributes[i].namespaceURI, container.attributes[i].name, container.attributes[i].value);
    }

    // "If new container has an id attribute, unset it."
    newContainer.removeAttribute("id");

    // "Insert new container into the parent of container immediately after
    // container."
    container.parentNode.insertBefore(newContainer, container.nextSibling);

    // "Let contained nodes be all nodes contained in new line range."
    var containedNodes = getAllContainedNodes(newLineRange);

    // "Let frag be the result of calling extractContents() on new line
    // range."
    var frag = newLineRange.extractContents();

    // "Unset the id attribute (if any) of each Element descendant of frag
    // that is not in contained nodes."
    var descendants = getDescendants(frag);
    for (var i = 0; i < descendants.length; i++) {
      if (descendants[i].nodeType == Node.ELEMENT_NODE
      && containedNodes.indexOf(descendants[i]) == -1) {
        descendants[i].removeAttribute("id");
      }
    }

    // "Call appendChild(frag) on new container."
    newContainer.appendChild(frag);

    // "While container's lastChild is a prohibited paragraph child, set
    // container to its lastChild."
    while (isProhibitedParagraphChild(container.lastChild)) {
      container = container.lastChild;
    }

    // "While new container's lastChild is a prohibited paragraph child,
    // set new container to its lastChild."
    while (isProhibitedParagraphChild(newContainer.lastChild)) {
      newContainer = newContainer.lastChild;
    }

    // "If container has no visible children, call createElement("br") on
    // the context object, and append the result as the last child of
    // container."
    if (![].some.call(container.childNodes, isVisible)) {
      container.appendChild(document.createElement("br"));
    }

    // "If new container has no visible children, call createElement("br")
    // on the context object, and append the result as the last child of
    // new container."
    if (![].some.call(newContainer.childNodes, isVisible)) {
      newContainer.appendChild(document.createElement("br"));
    }

    // "Call collapse(new container, 0) on the context object's Selection."
    getSelection().collapse(newContainer, 0);
    getActiveRange().setStart(newContainer, 0);
    getActiveRange().setEnd(newContainer, 0);

    // "Return true."
    return true;
  }
};

//@}
///// The insertText command /////
//@{
commands.inserttext = {
  action: function(value) {
    // "Delete the selection, with strip wrappers false."
    deleteSelection({stripWrappers: false});

    // "If the active range's start node is neither editable nor an editing
    // host, return true."
    if (!isEditable(getActiveRange().startContainer)
    && !isEditingHost(getActiveRange().startContainer)) {
      return true;
    }

    // "If value's length is greater than one:"
    if (value.length > 1) {
      // "For each element el in value, take the action for the
      // insertText command, with value equal to el."
      for (var i = 0; i < value.length; i++) {
        commands.inserttext.action(value[i]);
      }

      // "Return true."
      return true;
    }

    // "If value is the empty string, return true."
    if (value == "") {
      return true;
    }

    // "If value is a newline (U+00A0), take the action for the
    // insertParagraph command and return true."
    if (value == "\n") {
      commands.insertparagraph.action();
      return true;
    }

    // "Let node and offset be the active range's start node and offset."
    var node = getActiveRange().startContainer;
    var offset = getActiveRange().startOffset;

    // "If node has a child whose index is offset − 1, and that child is a
    // Text node, set node to that child, then set offset to node's
    // length."
    if (0 <= offset - 1
    && offset - 1 < node.childNodes.length
    && node.childNodes[offset - 1].nodeType == Node.TEXT_NODE) {
      node = node.childNodes[offset - 1];
      offset = getNodeLength(node);
    }

    // "If node has a child whose index is offset, and that child is a Text
    // node, set node to that child, then set offset to zero."
    if (0 <= offset
    && offset < node.childNodes.length
    && node.childNodes[offset].nodeType == Node.TEXT_NODE) {
      node = node.childNodes[offset];
      offset = 0;
    }

    // "Record current overrides, and let overrides be the result."
    var overrides = recordCurrentOverrides();

    // "Call collapse(node, offset) on the context object's Selection."
    getSelection().collapse(node, offset);
    getActiveRange().setStart(node, offset);
    getActiveRange().setEnd(node, offset);

    // "Canonicalize whitespace at (node, offset)."
    canonicalizeWhitespace(node, offset);

    // "Let (node, offset) be the active range's start."
    node = getActiveRange().startContainer;
    offset = getActiveRange().startOffset;

    // "If node is a Text node:"
    if (node.nodeType == Node.TEXT_NODE) {
      // "Call insertData(offset, value) on node."
      node.insertData(offset, value);

      // "Call collapse(node, offset) on the context object's Selection."
      getSelection().collapse(node, offset);
      getActiveRange().setStart(node, offset);

      // "Call extend(node, offset + 1) on the context object's
      // Selection."
      //
      // Work around WebKit bug: the extend() can throw if the text we're
      // adding is trailing whitespace.
      try { getSelection().extend(node, offset + 1); } catch(e) {}
      getActiveRange().setEnd(node, offset + 1);

    // "Otherwise:"
    } else {
      // "If node has only one child, which is a collapsed line break,
      // remove its child from it."
      //
      // FIXME: IE incorrectly returns false here instead of true
      // sometimes?
      if (node.childNodes.length == 1
      && isCollapsedLineBreak(node.firstChild)) {
        node.removeChild(node.firstChild);
      }

      // "Let text be the result of calling createTextNode(value) on the
      // context object."
      var text = document.createTextNode(value);

      // "Call insertNode(text) on the active range."
      getActiveRange().insertNode(text);

      // "Call collapse(text, 0) on the context object's Selection."
      getSelection().collapse(text, 0);
      getActiveRange().setStart(text, 0);

      // "Call extend(text, 1) on the context object's Selection."
      getSelection().extend(text, 1);
      getActiveRange().setEnd(text, 1);
    }

    // "Restore states and values from overrides."
    restoreStatesAndValues(overrides);

    // "Canonicalize whitespace at the active range's start, with fix
    // collapsed space false."
    canonicalizeWhitespace(getActiveRange().startContainer, getActiveRange().startOffset, false);

    // "Canonicalize whitespace at the active range's end, with fix
    // collapsed space false."
    canonicalizeWhitespace(getActiveRange().endContainer, getActiveRange().endOffset, false);

    // "If value is a space character, autolink the active range's start."
    if (/^[ \t\n\f\r]$/.test(value)) {
      autolink(getActiveRange().startContainer, getActiveRange().startOffset);
    }

    // "Call collapseToEnd() on the context object's Selection."
    //
    // Work around WebKit bug: sometimes it blows up the selection and
    // throws, which we don't want.
    try { getSelection().collapseToEnd(); } catch(e) {}
    getActiveRange().collapse(false);

    // "Return true."
    return true;
  }
};

//@}
///// The insertUnorderedList command /////
//@{
commands.insertunorderedlist = {
  preservesOverrides: true,
  // "Toggle lists with tag name "ul", then return true."
  action: function() { toggleLists("ul"); return true },
  // "True if the selection's list state is "mixed" or "mixed ul", false
  // otherwise."
  indeterm: function() { return /^mixed( ul)?$/.test(getSelectionListState()) },
  // "True if the selection's list state is "ul", false otherwise."
  state: function() { return getSelectionListState() == "ul" },
};

//@}
///// The justifyCenter command /////
//@{
commands.justifycenter = {
  preservesOverrides: true,
  // "Justify the selection with alignment "center", then return true."
  action: function() { justifySelection("center"); return true },
  indeterm: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if among visible editable nodes that
    // are contained in the result and have no children, at least one has
    // alignment value "center" and at least one does not. Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.some(function(node) { return getAlignmentValue(node) == "center" })
      && nodes.some(function(node) { return getAlignmentValue(node) != "center" });
  }, state: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if there is at least one visible
    // editable node that is contained in the result and has no children,
    // and all such nodes have alignment value "center".  Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.length
      && nodes.every(function(node) { return getAlignmentValue(node) == "center" });
  }, value: function() {
    // "Return the empty string if the active range is null.  Otherwise,
    // block-extend the active range, and return the alignment value of the
    // first visible editable node that is contained in the result and has
    // no children. If there is no such node, return "left"."
    if (!getActiveRange()) {
      return "";
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    if (nodes.length) {
      return getAlignmentValue(nodes[0]);
    } else {
      return "left";
    }
  },
};

//@}
///// The justifyFull command /////
//@{
commands.justifyfull = {
  preservesOverrides: true,
  // "Justify the selection with alignment "justify", then return true."
  action: function() { justifySelection("justify"); return true },
  indeterm: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if among visible editable nodes that
    // are contained in the result and have no children, at least one has
    // alignment value "justify" and at least one does not. Otherwise
    // return false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.some(function(node) { return getAlignmentValue(node) == "justify" })
      && nodes.some(function(node) { return getAlignmentValue(node) != "justify" });
  }, state: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if there is at least one visible
    // editable node that is contained in the result and has no children,
    // and all such nodes have alignment value "justify".  Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.length
      && nodes.every(function(node) { return getAlignmentValue(node) == "justify" });
  }, value: function() {
    // "Return the empty string if the active range is null.  Otherwise,
    // block-extend the active range, and return the alignment value of the
    // first visible editable node that is contained in the result and has
    // no children. If there is no such node, return "left"."
    if (!getActiveRange()) {
      return "";
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    if (nodes.length) {
      return getAlignmentValue(nodes[0]);
    } else {
      return "left";
    }
  },
};

//@}
///// The justifyLeft command /////
//@{
commands.justifyleft = {
  preservesOverrides: true,
  // "Justify the selection with alignment "left", then return true."
  action: function() { justifySelection("left"); return true },
  indeterm: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if among visible editable nodes that
    // are contained in the result and have no children, at least one has
    // alignment value "left" and at least one does not. Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.some(function(node) { return getAlignmentValue(node) == "left" })
      && nodes.some(function(node) { return getAlignmentValue(node) != "left" });
  }, state: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if there is at least one visible
    // editable node that is contained in the result and has no children,
    // and all such nodes have alignment value "left".  Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.length
      && nodes.every(function(node) { return getAlignmentValue(node) == "left" });
  }, value: function() {
    // "Return the empty string if the active range is null.  Otherwise,
    // block-extend the active range, and return the alignment value of the
    // first visible editable node that is contained in the result and has
    // no children. If there is no such node, return "left"."
    if (!getActiveRange()) {
      return "";
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    if (nodes.length) {
      return getAlignmentValue(nodes[0]);
    } else {
      return "left";
    }
  },
};

//@}
///// The justifyRight command /////
//@{
commands.justifyright = {
  preservesOverrides: true,
  // "Justify the selection with alignment "right", then return true."
  action: function() { justifySelection("right"); return true },
  indeterm: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if among visible editable nodes that
    // are contained in the result and have no children, at least one has
    // alignment value "right" and at least one does not. Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.some(function(node) { return getAlignmentValue(node) == "right" })
      && nodes.some(function(node) { return getAlignmentValue(node) != "right" });
  }, state: function() {
    // "Return false if the active range is null.  Otherwise, block-extend
    // the active range. Return true if there is at least one visible
    // editable node that is contained in the result and has no children,
    // and all such nodes have alignment value "right".  Otherwise return
    // false."
    if (!getActiveRange()) {
      return false;
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    return nodes.length
      && nodes.every(function(node) { return getAlignmentValue(node) == "right" });
  }, value: function() {
    // "Return the empty string if the active range is null.  Otherwise,
    // block-extend the active range, and return the alignment value of the
    // first visible editable node that is contained in the result and has
    // no children. If there is no such node, return "left"."
    if (!getActiveRange()) {
      return "";
    }
    var nodes = getAllContainedNodes(blockExtend(getActiveRange()), function(node) {
      return isEditable(node) && isVisible(node) && !node.hasChildNodes();
    });
    if (nodes.length) {
      return getAlignmentValue(nodes[0]);
    } else {
      return "left";
    }
  },
};

//@}
///// The outdent command /////
//@{
commands.outdent = {
  preservesOverrides: true,
  action: function() {
    // "Let items be a list of all lis that are ancestor containers of the
    // range's start and/or end node."
    //
    // It's annoying to get this in tree order using functional stuff
    // without doing getDescendants(document), which is slow, so I do it
    // imperatively.
    var items = [];
    (function(){
      for (
        var ancestorContainer = getActiveRange().endContainer;
        ancestorContainer != getActiveRange().commonAncestorContainer;
        ancestorContainer = ancestorContainer.parentNode
      ) {
        if (isHtmlElement(ancestorContainer, "li")) {
          items.unshift(ancestorContainer);
        }
      }
      for (
        var ancestorContainer = getActiveRange().startContainer;
        ancestorContainer;
        ancestorContainer = ancestorContainer.parentNode
      ) {
        if (isHtmlElement(ancestorContainer, "li")) {
          items.unshift(ancestorContainer);
        }
      }
    })();

    // "For each item in items, normalize sublists of item."
    items.forEach(normalizeSublists);

    // "Block-extend the active range, and let new range be the result."
    var newRange = blockExtend(getActiveRange());

    // "Let node list be a list of nodes, initially empty."
    //
    // "For each node node contained in new range, append node to node list
    // if the last member of node list (if any) is not an ancestor of node;
    // node is editable; and either node has no editable descendants, or is
    // an ol or ul, or is an li whose parent is an ol or ul."
    var nodeList = getContainedNodes(newRange, function(node) {
      return isEditable(node)
        && (!getDescendants(node).some(isEditable)
        || isHtmlElement(node, ["ol", "ul"])
        || (isHtmlElement(node, "li") && isHtmlElement(node.parentNode, ["ol", "ul"])));
    });

    // "While node list is not empty:"
    while (nodeList.length) {
      // "While the first member of node list is an ol or ul or is not
      // the child of an ol or ul, outdent it and remove it from node
      // list."
      while (nodeList.length
      && (isHtmlElement(nodeList[0], ["OL", "UL"])
      || !isHtmlElement(nodeList[0].parentNode, ["OL", "UL"]))) {
        outdentNode(nodeList.shift());
      }

      // "If node list is empty, break from these substeps."
      if (!nodeList.length) {
        break;
      }

      // "Let sublist be a list of nodes, initially empty."
      var sublist = [];

      // "Remove the first member of node list and append it to sublist."
      sublist.push(nodeList.shift());

      // "While the first member of node list is the nextSibling of the
      // last member of sublist, and the first member of node list is not
      // an ol or ul, remove the first member of node list and append it
      // to sublist."
      while (nodeList.length
      && nodeList[0] == sublist[sublist.length - 1].nextSibling
      && !isHtmlElement(nodeList[0], ["OL", "UL"])) {
        sublist.push(nodeList.shift());
      }

      // "Record the values of sublist, and let values be the result."
      var values = recordValues(sublist);

      // "Split the parent of sublist, with new parent null."
      splitParent(sublist);

      // "Fix disallowed ancestors of each member of sublist."
      sublist.forEach(fixDisallowedAncestors);

      // "Restore the values from values."
      restoreValues(values);
    }

    // "Return true."
    return true;
  }
};

//@}

//////////////////////////////////
///// Miscellaneous commands /////
//////////////////////////////////

///// The defaultParagraphSeparator command /////
//@{
commands.defaultparagraphseparator = {
  action: function(value) {
    // "Let value be converted to ASCII lowercase. If value is then equal
    // to "p" or "div", set the context object's default single-line
    // container name to value and return true. Otherwise, return false."
    value = value.toLowerCase();
    if (value == "p" || value == "div") {
      defaultSingleLineContainerName = value;
      return true;
    }
    return false;
  }, value: function() {
    // "Return the context object's default single-line container name."
    return defaultSingleLineContainerName;
  },
};

//@}
///// The selectAll command /////
//@{
commands.selectall = {
  // Note, this ignores the whole globalRange/getActiveRange() thing and
  // works with actual selections.  Not suitable for autoimplementation.html.
  action: function() {
    // "Let target be the body element of the context object."
    var target = document.body;

    // "If target is null, let target be the context object's
    // documentElement."
    if (!target) {
      target = document.documentElement;
    }

    // "If target is null, call getSelection() on the context object, and
    // call removeAllRanges() on the result."
    if (!target) {
      getSelection().removeAllRanges();

    // "Otherwise, call getSelection() on the context object, and call
    // selectAllChildren(target) on the result."
    } else {
      getSelection().selectAllChildren(target);
    }

    // "Return true."
    return true;
  }
};

//@}
///// The styleWithCSS command /////
//@{
commands.stylewithcss = {
  action: function(value) {
    // "If value is an ASCII case-insensitive match for the string
    // "false", set the CSS styling flag to false. Otherwise, set the
    // CSS styling flag to true.  Either way, return true."
    cssStylingFlag = String(value).toLowerCase() != "false";
    return true;
  }, state: function() { return cssStylingFlag }
};

//@}
///// The useCSS command /////
//@{
commands.usecss = {
  action: function(value) {
    // "If value is an ASCII case-insensitive match for the string "false",
    // set the CSS styling flag to true. Otherwise, set the CSS styling
    // flag to false.  Either way, return true."
    cssStylingFlag = String(value).toLowerCase() == "false";
    return true;
  }
};
//@}

// Some final setup
//@{
(function() {
// Opera 11.50 doesn't implement Object.keys, so I have to make an explicit
// temporary, which means I need an extra closure to not leak the temporaries
// into the global namespace.  >:(
var commandNames = [];
for (var command in commands) {
  commandNames.push(command);
}
commandNames.forEach(function(command) {
  // "If a command does not have a relevant CSS property specified, it
  // defaults to null."
  if (!("relevantCssProperty" in commands[command])) {
    commands[command].relevantCssProperty = null;
  }

  // "If a command has inline command activated values defined but nothing
  // else defines when it is indeterminate, it is indeterminate if among
  // formattable nodes effectively contained in the active range, there is at
  // least one whose effective command value is one of the given values and
  // at least one whose effective command value is not one of the given
  // values."
  if ("inlineCommandActivatedValues" in commands[command]
  && !("indeterm" in commands[command])) {
    commands[command].indeterm = function() {
      if (!getActiveRange()) {
        return false;
      }

      var values = getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode)
        .map(function(node) { return getEffectiveCommandValue(node, command) });

      var matchingValues = values.filter(function(value) {
        return commands[command].inlineCommandActivatedValues.indexOf(value) != -1;
      });

      return matchingValues.length >= 1
        && values.length - matchingValues.length >= 1;
    };
  }

  // "If a command has inline command activated values defined, its state is
  // true if either no formattable node is effectively contained in the
  // active range, and the active range's start node's effective command
  // value is one of the given values; or if there is at least one
  // formattable node effectively contained in the active range, and all of
  // them have an effective command value equal to one of the given values."
  if ("inlineCommandActivatedValues" in commands[command]) {
    commands[command].state = function() {
      if (!getActiveRange()) {
        return false;
      }

      var nodes = getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode);

      if (nodes.length == 0) {
        return commands[command].inlineCommandActivatedValues
          .indexOf(getEffectiveCommandValue(getActiveRange().startContainer, command)) != -1;
      } else {
        return nodes.every(function(node) {
          return commands[command].inlineCommandActivatedValues
            .indexOf(getEffectiveCommandValue(node, command)) != -1;
        });
      }
    };
  }

  // "If a command is a standard inline value command, it is indeterminate if
  // among formattable nodes that are effectively contained in the active
  // range, there are two that have distinct effective command values. Its
  // value is the effective command value of the first formattable node that
  // is effectively contained in the active range; or if there is no such
  // node, the effective command value of the active range's start node; or
  // if that is null, the empty string."
  if ("standardInlineValueCommand" in commands[command]) {
    commands[command].indeterm = function() {
      if (!getActiveRange()) {
        return false;
      }

      var values = getAllEffectivelyContainedNodes(getActiveRange())
        .filter(isFormattableNode)
        .map(function(node) { return getEffectiveCommandValue(node, command) });
      for (var i = 1; i < values.length; i++) {
        if (values[i] != values[i - 1]) {
          return true;
        }
      }
      return false;
    };

    commands[command].value = function() {
      if (!getActiveRange()) {
        return "";
      }

      var refNode = getAllEffectivelyContainedNodes(getActiveRange(), isFormattableNode)[0];

      if (typeof refNode == "undefined") {
        refNode = getActiveRange().startContainer;
      }

      var ret = getEffectiveCommandValue(refNode, command);
      if (ret === null) {
        return "";
      }
      return ret;
    };
  }

  // "If a command preserves overrides, then before taking its action, the
  // user agent must record current overrides. After taking the action, if
  // the active range is collapsed, it must restore states and values from
  // the recorded list."
  if ("preservesOverrides" in commands[command]) {
    var oldAction = commands[command].action;

    commands[command].action = function(value) {
      var overrides = recordCurrentOverrides();
      var ret = oldAction(value);
      if (getActiveRange().collapsed) {
        restoreStatesAndValues(overrides);
      }
      return ret;
    };
  }
});
})();
//@}

// vim: foldmarker=@{,@} foldmethod=marker
